Dr. Jack Shephard is a former spinal surgeon and was the de facto leader of the survivors following the crash of Oceanic Flight 815. Before the crash, Jack had control issues and trouble dealing with situations that he couldn't fix, which led to the deterioration of his marriage and the relationship with his father. However, on the Island, this ability to solve problems through reason made him able to function well during a crisis and lead several A-Missions. He was commonly looked upon as the leader of the survivors and was on good terms with everyone, especially Kate and Juliet. He blew open the Hatch and pushed the button with John Locke where the two of them had issues working together because John was a "man of faith" while Jack was a "man of science". He was later captured by the Others, along with Kate and Sawyer, as part of Michael's betrayal. While with the Others, Jack performed surgery on their leader, Benjamin Linus in exchange for leaving the island but was unable to leave after Locke blew up the submarine. After calling the freighter, Jack and five other survivors managed to escape the Island by using a helicopter, although they were forced to leave everyone else behind when Ben moved the Island. Since the rescue, Jack learned of his family relation to Claire and Aaron, laid his father to rest and became engaged to Kate. Unfortunately, certain events, including a visit from Jeremy Bentham and visions of his father, caused his resolve to collapse and made him determined to return to the island. With Ben's help, Jack later returned to the island after being thrown through time and space when Ajira Flight 316 flew over the Island. After finding himself stuck in 1977 he worked for the DHARMA Initiative as a workman where he tried to change the past by detonating a hydrogen bomb. After the detonation he time traveled to his original timeline of 2007 having survived the blast.
Jack Shephard is the son of Dr. Christian and Margo Shephard. He was also, through his father, the half-brother of fellow Oceanic Flight 815 survivor Claire Littleton, thus making him the half-uncle of Claire's son, Aaron. As an adolescent, Jack was beaten by a teenage bully after attempting to rescue his friend Marc Silverman. Jack later explained the cause of his injuries to his intoxicated father, who informed him over a glass of whiskey of his own ability to cope with the consequences of difficult life and death decisions. He advised Jack not to attempt to be a hero because he didn't have what it took to cope with failing. ("White Rabbit")
At some point during his lifetime, Jack took a small number of flying lessons, but chose not to continue with them because "it wasn't for me." ("Pilot, Part 1")
Jack attended Columbia University and then graduated from UCLA medical school a year faster than anyone else. ("A Tale of Two Cities") Following this, Jack began working with his father at St. Sebastian Hospital as a spinal surgeon. ("All the Best Cowboys Have Daddy Issues")
During his residency, Jack was in surgery, operating on a teenage girl. He accidentally nicked her dural sac and went into a panic. Christian told him to count to five, and that if Jack didn't calm down Christian would do the surgery himself. Jack pulled himself together and fixed the problem. Later, after his candy bar got stuck in the vending machine, Jack told Christian that he was angry that he was "put in a time-out" and disrespected in front of his team. As he started to walk away, Jacob approached Jack and offered him the Apollo Candy Bar that was stuck in the vending machine. He touched Jack's hand for a moment and said, "Maybe all it needed was a little push." ("The Incident, Parts 1 & 2")
At around 8:15 AM on an unknown date in 2001, Jack was presented with two victims of a head-on collision involving two SUVs. Jack chose to save the woman, Sarah, whose spine was severely damaged, at the older man's expense. ("Man of Science, Man of Faith") Afterwards, he passed the man's daughter. ("Abandoned") Upon Sarah's inquiries regarding her condition, Jack told her she would never walk again. Christian overheard this and advised his son to be more optimistic in his dealings with patients. Jack informed Sarah's fiance Kevin of the extent of her injuries and became annoyed when Kevin appeared to question whether he wanted to continue his relationship with Sarah. While preparing for surgery, Jack overstepped his professional relationship with Sarah, promising to fix her.
After what he felt was an unsuccessful surgery, Jack left the hospital for a nearby stadium, where he began a tour de stade. Another man was there doing the same thing, and as Jack tried to outrun him, he fell and hurt his ankle. The stranger came to Jack's aid and introduced himself as Desmond. He intuitively guessed Jack was worried about a woman and hypothetically questioned whether Jack had really failed to fix her. Desmond also explained that he too was once "almost a doctor." He gave Jack the advice to "lift it up," ostensibly referring to the injured ankle, though the phrase may have had a more philosophical meaning. Desmond left, promising to see Jack "in another life."
Jack went back to the hospital and tearfully informed Sarah of his failure to reverse the damage to her spine. She accused him of "yanking her chain," claiming she could wiggle her toes. Jack examined her legs and concluded he had indeed fixed her as he had promised. ("Man of Science, Man of Faith")
Some time later, likely in 2002, Jack's childhood friend Marc Silverman expressed his fears about giving a toast at Jack's upcoming rehearsal dinner. Jack tried to allay those fears, telling his friend there was still time to back out. Silverman planned to drink heavily beforehand, claiming eight beers should be enough to calm his nerves. Following Marc's speech at the rehearsal, Sarah gave a toast to Jack. She cited him as heroic and highly committed, and said because of him she would be able to dance at their wedding. Jack and Sarah spoke later while playing a duet on a piano in the hotel in which the wedding was to be held. During this conversation, Sarah attempted to calm Jack's nerves about the vows they had promised to write. Jack's father arrived later that night and found Jack dangling his feet in the hotel pool. Christian joined him and listened as Jack told him he was having difficulty writing his vows and feared he was only marrying Sarah because he had saved her life two years before. Christian complimented his son on his ability to remain absolutely committed, but thought it made him "not good at letting go." Some hours before the wedding, Christian joined Jack as he stood on the beach throwing rocks into the ocean and presented him with the watch his own father had given him on his wedding day. Christian explained that he had never worn the watch because his father had disapproved of his marrying Margo. Christian gave the watch to Jack, asking him to be a better father than himself. Later, at the wedding, Jack improvised his vows, telling Sarah of his belief that rather than his having fixed her, she had fixed him, and of his resulting unconditional love for her. ("Do No Harm"), ("The Watch")
In early December of 2003, Jack and his father were approached by a wealthy Italian man named Angelo Busoni who had, after being diagnosed with a spinal tumor, chosen to be treated at St. Sebastian Hospital because of the miracle Jack had performed on Sarah. Christian, who was at that time Chief of Surgery, believed the elderly man's tumor was inoperable and, although Jack shared Christian's opinion and was aware of the differences between his current patient's condition and that of his wife, he nonetheless agreed to operate. Jack's subsequent dedication to his patient and a dangerous level of association with his daughter Gabriela, put a strain on his marriage. After Angelo's death as a result of heart failure on the operating table, Jack and Gabriela shared a kiss, though afterward Jack pulled away and said he couldn't do it (the implication being that he could not pursue a relationship with her). He returned home to Sarah resolved to fix his marriage. When he confessed the kiss to his wife and began to say how he would change, Sarah told him she had been seeing another man and had already made plans to leave Jack, citing his compulsive obsession with fixing things. ("The Hunting Party")
In February 2004, Jack stalked his estranged wife, waiting outside the kindergarten at which she taught. Enraged with jealousy, Jack bitterly contested the divorce and became obsessed with discovering the identity of Sarah's lover. At one point, he fired his lawyer and offered Sarah all his possessions in exchange for the man's name, a demand she ignored. Later, having somehow acquired her cell phone, Jack began calling all of Sarah's contacts, convinced that one of them was her new lover. He dialed a number in his father's presence and Christian's phone began to ring, causing Jack to believe it was Christian who had stolen his wife. Upon being asked why Sarah would be calling him, Christian demanded that his son let her go. Ignoring this, Jack repeated his question and Christian told him Sarah was concerned about Jack's obsession. Jack replied that, despite being "a drunk," his father would not know what it meant to be obsessive.
Later, while discussing a patient's treatment with a nurse Jack overheard Christian laughing into his phone. Jack assumed that Christian was talking to Sarah. He followed his father to the Lynford Hotel and into an Alcoholics Anonymous meeting. After a brief confrontation in which Jack demanded to see his father's cell phone and mocked his achievement of staying sober for fifty days, Jack outright accused Christian of sleeping with his wife. Shortly after, Jack physically attacked his father, an action which resulted in his arrest and subsequent jailing. Jack was bailed out by his former wife, who had been informed of Jack's incarceration by an extremely drunk Christian Shephard over the phone. Jack again probed Sarah for information regarding her new boyfriend, but she refused to answer, and left the building. Jack chased after Sarah outside and, seeing a man standing by a car across the street, asked Sarah if that was he (her lover). Sarah said it didn't matter, but that Jack should be happy he once again had something to fix. ("A Tale of Two Cities")
Following the collapse of his marriage, Jack took a trip to Thailand to relax. While there, he met a mysterious woman named Achara. They became friends and occasionally slept together. Jack tried to find out what she did for a living, but she was very secretive about her work. Jack followed her one night. When he confronted her, Achara told him she saw into people and translated what she saw into tattoos. Jack grew strangely forceful and demanded to know what she saw in him. Achara became very emotional and told Jack she saw him as a leader who, although strong, could also be unhappy. Jack insisted she tattoo him. Achara warned there would be consequences, but gave in. The tattoo that Achara designed on Jack's arm translates to "He walks among us, but is not one of us." The next day, when Jack emerged from his tent on the beach, the people he had befriended earlier attacked him violently. They screamed at him, telling him to leave and never return. As Jack struggled to get up he saw Achara watching sadly from a short distance away. ("Stranger in a Strange Land")
In July of 2004, Jack was called into surgery by one of the operating nurses, who had observed his intoxicated father mistakenly cut the hepatic artery of a patient. Taking over his father's role as surgeon-of-record, Jack attempted to rectify the error; however, despite resealing the woman's artery, her rapid blood loss and resulting cardiac arrest caused her death. After the surgery, a confrontation ensued between the two Shephards, during which Christian said his son had no right barging into his surgery. Jack contended that his actions were justified, given his father's impaired state at the time of the surgery. A short time later, Jack was called into his father's office and asked to sign a falsified report of the woman's death, which stated that Jack had accompanied his father during the surgery, but in spite of their "most valiant efforts," the woman had died of massive blood loss caused by her severe internal injuries. Although Jack initially refused to sign the document, stating that his father deserved to face the consequences of his actions - including the revocation of his license - his father ultimately goaded him into it. Following this meeting, Jack witnessed his father consoling the deceased woman's husband, who was threatening legal action against the hospital for his wife's death. This, in addition to Jack's discovery of the woman's pregnancy at the time of the surgery, caused Jack to revise his statement to the panel responsible for determining whether any action should be taken regarding her death. Rather than agreeing with what had been written in Christian's falsified report, Jack revealed the truth about what had occurred during the surgery, concluding with his belief that his intoxicated father's actions, rather than the woman's injuries, were the direct cause of her death. ("All the Best Cowboys Have Daddy Issues")
In mid-September of 2004, at the behest of his frantically worried mother Margo, Jack traveled to Sydney, Australia in search of his missing father, despite their lack of communication in the previous few months. Jack searched his father's hotel room and found his wallet, some alcohol, and a collection of pills. He later learned his father had died due to an alcohol-induced heart attack. He attempted to load his father's body onto the same plane on which he was to return to America, but had trouble getting the casket on the plane because he had not made the proper arrangements. ("White Rabbit")
However, after a heartfelt plea to an Oceanic Airlines ticket agent named Chrissy, in which Jack stated his need for closure regarding his father's death, he was able to have the coffin loaded onto the plane.("White Rabbit")
Just prior to boarding Oceanic Flight 815, after his conversation with Chrissy, Jack met Ana Lucia Cortez in an airport bar. Ana Lucia was assigned to seat 42F on the same flight. Jack mentioned his father's death, as well as the fact that he had once been married. Ana Lucia stated her opinion that children should not work with their parents. When Ana Lucia received a phone call, she left, but promised to have another drink with Jack on the plane. ("Exodus, Part 1")
Jack sat in seat 23B, and had a conversation with Australian flight attendant Cindy Chandler, who handed him two airline bottles of vodka, one of which he consumed immediately. A short time after this, while rising from his seat, Jack was nearly knocked down by a man hurrying up the aisle. This prompted a conversation with nearby passenger Rose Nadler, whose husband Bernard was in the bathroom. After Rose's reaction to some light turbulence, Jack attempted to allay her fears. Very soon, however, the plane began to shake more violently before making a sharp, uncontrolled descent. Due to the loss of cabin pressure, oxygen masks fell from the ceiling of the plane. Despite putting his mask on, Jack blacked out before the plane's tail separated from the mid-section. ("Pilot, Part 1")
Jack woke up alone in a bamboo thicket near the site of the plane crash. He looked over to see a dog run past him. He stood up and took a bottle of vodka from his jacket pocket, then began to run through the jungle toward the sound of screaming. The plane had crashed on the beach and Jack began helping the injured passengers. There was a man whose leg was being crushed under one of the detached landing wheels, and Jack enlisted the help of another survivor to help him move it. After the man was free, Jack turned around to see a pregnant woman on the beach crying for help. He was starting in her direction when a man was sucked into the engine. As it blew up, Jack shielded the woman from the explosion, then asked another survivor named Hurley to look after her so he could help Rose, who wasn't breathing. A young man named Boone was trying to give her CPR, but Jack shooed him away because he was doing it wrong. After reviving Rose, he noticed the plane's wing beginning to fall and he pushed Claire and Hurley out of its way.
Jack wandered through the wreckage on the beach, then took a sewing kit from a suitcase and found a quiet place to examine his own wounds. A woman walked by and Jack asked for her help in stitching him up. Kate seemed terrified, but Jack calmed her by telling her about his first solo surgery, where he conquered his fear during an emergency by "letting the fear in," but only for five seconds.
The next day Jack, Kate and Charlie hiked into the jungle to find the cockpit. Once inside, they found the pilot alive. He gave them the transceiver shortly before being pulled out the window by the Monster. Kate, Jack and Charlie ran from the cockpit and into the jungle. After a brief rainstorm, they found the pilot dead in a tree. ("Pilot, Part 1")
They returned to camp, where Jack broke up a fight between Sayid and Sawyer. Kate gave the transceiver to Sayid so he could fix it and Jack went to take a look at the man with the shrapnel. ("Pilot, Part 2") He asked Hurley to hold the man down while he tried to take the shrapnel out. Hurley fainted and Jack had to complete the surgery himself. At one point, the man woke up and forcefully told Jack, "Don't trust her," and asked for his handcuffs. When Jack asked whom he was talking about, the Marshal directed him to look in his jacket pocket. Inside, Jack found a mugshot of Kate. Hurley later came across it, but Jack told him he wasn't interested in knowing what her crime was.
He went to look for some stronger antibiotics and found Sawyer looting in the fuselage. When he got back to the tent, the Marshal was trying to strangle Kate. Jack broke them up as Mars went into convulsions. Kate asked Jack to put him out of his misery, but Jack told her he had seen her mugshot and that he was not a murderer. Mars wanted to talk to Kate alone and Jack agreed. When Hurley told him Kate had a gun, he ran to the tent, reaching it just as Kate walked out. A gunshot rang out and Kate walked away as Sawyer left the tent. He told Jack the Marshal had asked to be shot. A second later, choking and coughing sounds came from the tent, and Jack went to euthanize the Marshal to end his suffering. ("Tabula Rasa")
When wild boars started raiding the fuselage for the dead bodies, Jack decided the best way to dispose of the bodies was to burn the whole thing. Struggling with his leadership role, he didn't want to plan or lead the memorial, nor did he want to talk to Rose, who had been sitting on the beach staring into the ocean ever since the crash. When Boone pointed out that Jack had saved her life, he sat down next to her and tried to get her to talk. Rose said she would like to watch the funeral service that night, but when Jack asked her to say something about her husband, she told him Bernard was still alive. Jack looked toward the jungle and saw a man wearing a suit and white tennis shoes standing under a tree. Jack turned to go with Rose, and when he looked back the man was gone. ("Walkabout")
On day 6, Boone nearly died trying to save a woman from drowning. Jack rescued him, but felt guilty he couldn't save Joanna as well. He told Kate how he felt, and while talking to her, he saw his father standing in the water. Later, Boone berated him, telling him he could have made it back and Jack should have saved Joanna. Jack walked away from Boone, who was still ranting, when he saw his father again. He ran into the jungle and chased after him for a few hours before nearly falling off a cliff. Locke helped him up and Jack asked how everyone was doing back at camp. Locke told him they needed Jack to lead them, but Jack said he couldn't because he would fail. He told Locke he was going crazy, and Locke told him to keep chasing what he was after. Jack took his advice and eventually found some caves near a supply of fresh water. He also found his father's coffin. When he opened it and found it empty, he began beating it angrily with a metal pipe. Jack went back to the beach to tell everyone he had found water and shelter, telling them, "If we can't live together, we're going to die alone." ("White Rabbit")
Jack took Kate, Locke and Charlie to the caves to bring water back to the beach. Charlie stepped on a beehive and Jack and Kate got separated from the other two. They ran to the caves, where they found the skeletal remains of a man and a woman. Jack thought they must have lived in the caves and told Kate the survivors should move there, too. Not everyone wanted to move off the beach, and the group split. ("House of the Rising Sun")
When Jack became trapped by a cave-in, the survivors began a rescue attempt led by Michael. Charlie was the only one small enough to go in and who had no emotional attachments on the Island. Once inside the cave, he had to pop Jack's dislocated shoulder back into place. Jack told Charlie he knew he was going through withdrawals from heroin, and that night, after they had gotten out of the cave, Jack helped him through his pain and told everyone Charlie had the flu. ("The Moth")
While Jack was treating Sayid, who had been knocked out while trying to triangulate the signal for the transceiver, Boone came running into the caves, wounded. He told Jack he thought Sawyer had stolen Shanon's inhaler, and Sawyer had found him looking through his stuff trying to find it. Jack demanded Sawyer hand over the medicine, and Sawyer told Kate he would give her the inhalers for a kiss, which she refused. Later, with Jack's approval, Sayid tied Sawyer to a tree and tortured him for answers. Sawyer finally agreed to give up the inhalers, but only to Kate. He again said he would give her the medication if she kissed him, which she reluctantly did, only to find that he did not have the inhalers after all. Sayid became enraged and attacked Sawyer, stabbing him in the arm and hitting an artery. Luckily, Jack was there to stop the bleeding and save Sawyer's life. Sayid, ashamed of what he had done, left the beach. ("Confidence Man")
At Jack's infirmary in the caves, a man called Sullivan was worried about a rash. Jack told him to relax, but Hurley said everyone needed something to do. He built a golf course, and Jack and Michael were the first to play on it. ("Solitary")
Claire began having nightmares about someone trying to hurt her baby. Jack tried to convince her it was nothing to worry about, but Claire was adamant. After a particularly bad dream, Hurley decided it would be a good idea to take a census to get a better idea of whom they were living with. Just as Ethan came upon Claire and Charlie alone in the jungle, Hurley told Jack that Ethan wasn't on the plane. ("Raised by Another")
After discovering Claire and Charlie had been taken, Jack and Kate searched for Ethan. They got separated and Ethan attacked and threatened Jack before disappearing into the jungle again. Kate helped him up and a short time later they found Charlie hanging by his neck from a tree. Jack held his legs while Kate cut him down, then tried to revive him. Unable to let him go, Jack ignored Kate's pleas and pounded on Charlie's chest until he was finally able to breathe. ("All the Best Cowboys Have Daddy Issues")
After Kate had found the Marshal's Halliburton case, she asked Jack to help her open it. She also revealed that the key to the case was in the buried Marshal's wallet. Jack suspected that Kate had hidden motives, and asked her if anything else in the case was of importance to her. Kate claimed she only feared the guns would fall into Sawyer's hands. Jack told her he would only help if she promised they would open the case together. Kate agreed and they headed to where Mars was buried. When they had dug him up, Kate volunteered to reach in and get the wallet, and after obtaining it she jumped quickly out of the grave. When she opened the wallet, she acted disgusted to the maggots inside and threw it on the ground. Jack picked it up again, and looked inside but found no key. Kate acted surprised, but Jack saw through her con, and bitterly praised her attempts to hide the key while distracting him. He grabbed her hand and demanded she open it. Kate complied, revealing the key inside. Jack walked away with the key, refusing to let Kate explain herself.
Jack approached Sawyer and asked for the case. When Sawyer protested, Jack threatened to take him off his medication, inducing fear about the possible complications. Sawyer reluctantly handed Jack the case and asked him if Kate had revealed what was inside. Jack lied and said she hadn't. Sawyer warned Jack that Kate was lying about whatever reasons she had given him. Back at the caves, Kate and Jack opened the case. Jack was amazed to find that the contents were as Kate described, with the exception of a yellow envelope marked "Personal Effects," which he handed to Kate. She opened the envelope, and pulled out a small toy airplane. She told him that it had belonged to the man she killed. ("Whatever the Case May Be")
On day 27, Claire came back to the caves, but she seemed to have amnesia. After Ethan threatened Charlie and killed Scott, Jack revealed the gun case to Locke and they set up a trap, using Claire as bait. The plan worked, but after Jack beat Ethan to the ground, Charlie shot and killed him. ("Homecoming")
Jack's next challenge came on day 40, when Locke brought Boone to him, claiming he had fallen off a cliff. Jack wanted to amputate Boone's leg, and when Sun tried to stop him, he said, "Don't tell me what I can't do." He had a last minute change of heart when Boone awoke and told him he wanted Jack to let him go. Jack held Locke responsible for Boone's death and confronted him at the funeral. Even after Locke explained what had actually happened, his earlier lie and the the fact the he was keeping the Hatch a secret caused Jack to distrust him. ("Do No Harm") ("The Greater Good")
On day 44, Jack set out along with Kate, Rousseau, Locke, Hurley, and Arzt to get dynamite from the Black Rock to blow open the Hatch. ("Exodus, Part 1") On the way back, Jack and Kate kept Locke from being pulled down into a hole by the Monster. Jack, Kate, Locke, and Hurley arrived at the Hatch later that night. They set the dynamite on the hinge of the Hatch and were about to set it off when Hurley noticed the Numbers on the side. He yelled not to light it, but Locke lit the fuse anyway. Hurley tried to stamp out the fuse, repeating "the Numbers are bad." Jack tackled him and the dynamite exploded, revealing a deep, dark metal tunnel. Jack and Locke stared down into the pit before them, no idea of what might be at the bottom. ("Exodus, Part 2")
During the walk back from the Hatch, Hurley shared with Jack his story about the Numbers inscribed on the outside of the Hatch, but was disappointed by Jack's response. Upon reaching the caves, Jack explained the situation to the survivors, promising them they would be all right, as long as they stayed together. As Jack was about to finish this speech, Locke appeared, carrying cable and saying he was going into the Hatch. Soon after, Kate followed behind him. While Locke was easing her down the shaft, Kate realized that there was something in the Hatch, and in a sudden burst of light from within the Hatch, Kate mysteriously disappeared.
Back at the caves, Jack armed himself and set off after Kate and Locke. Upon reaching the Hatch and finding no one there, he rappelled down the shaft to look for the others. After being surprised by a bright light and loud music, he entered the Swan. He saw a computer and reached out to it, but Locke appeared and told him not to touch it. Jack raised the gun and asked where Kate was. Locke did not answer, as a man had a gun pointed at the side of his head. Locke told Jack to put the gun down. The man threatened that he would shoot Locke if Jack did not surrender. Jack refused, instead taunting Locke about his destiny. Finally, the man stepped out and Jack recognized him as the man he had previously met in 2001 while running in the stadium after Sarah's surgery. ("Man of Science, Man of Faith") ("Adrift")
When the computer was shot and a system failure seemed imminent, Desmond left the Swan and Jack and Locke became its main inhabitants. They had to input the Numbers into the computer every 108 minutes for an unknown reason. Tension grew between the two as it began to become their permanent home. ("Orientation")
Jack, alongside Kate, Locke, Sayid and Hurley continued to explore the Swan Station, but their investigations would be halted when, during a golf game, Kate and Jack came face to face with Mr. Eko, a tail-section survivor carrying an injured Sawyer over his shoulder. As Jack and Kate tended to the injured Sawyer the two factions of survivors collided and it was revealed that Shannon's life had been the cost. He reunited with Ana Lucia in the jungle and the tail-section survivors joined the mid-section under strained circumstances. As per her brother, Jack led Shannon's funeral. ("Everybody Hates Hugo") ("Collision") ("What Kate Did")
Jack had a very hard time accepting the mystery of the numbers, and relied on scientific fact alone to explain what was happening. This put him at odds with Locke, who relied purely on faith to explain his place on the Island and the seemingly meaningless task the Countdown Timer. Jack's relationship with Sawyer also became strained as he competed for Kate's attention, and shared a passionate kiss with her in the jungle. ("What Kate Did")
After Michael locked up Jack and Locke in the armory, Kate and Sawyer came to the Swan Station and opened the armory door. The A-team decided to look for Michael and try to save him. Jack and John said yes to Sawyer’s offer to join them but denied Kate’s. On their trek, they heard seven gun shots. They ran towards the sounds, hoping to find Michael alive. That night, the three of them argue after Locke lost Michael's track. Their disagreement was interrupted by the same bearded man who had stolen Walt off the raft. The bearded man said Michael wasn't going to find them and that Walt was fine. He then chastised the survivors for intruding on “their” island. Jack said he didn't believe him and that Locke, Sawyer, and himself outnumbered the Others. In a moment, a ring of torches lit up, and the hunting party discovered they were surrounded. The bearded man warned the three of them that there was a line where they stood, and they were not allowed to cross it. If they did, they would go from "misunderstanding" to "something else." Jack opposed this suggestion. Tom was forced to perform his plan B - a head-bagged Kate was handed to the man, who made the hunting party hand over all their guns so Kate could go free. The Others disappeared, and the four castaways returned to camp without having accomplished anything. Kate later tried to apologize to Jack, but he gave her the cold shoulder. ("The Hunting Party")
The rivalry between Locke and Jack began to escalate into a leadership struggle, which came to a head when Locke allowed Sayid to torture a man calling himself Henry Gale who Sayid thought might be one of the Others. The man's screams led Jack to force Locke to open the armory door just as the timer began to sound. Jack said that if Locke did not open the door he would not let him push the button. Locke did not believe that Jack would risk everybody's life on the Island, but Jack said he didn't think anything would happen if the button was not pushed. Locke eventually opened the door, then rushed to enter the code and push the button, but his fingers tripped over themselves and he didn't get them entered in time. The survivors saw for the first time what happened if the timer ran past 108 minutes. ("One of Them")
Henry took advantage of the antagonism between Jack and Locke, trying to play them against each other. He often convinced Locke that Jack was controlling him and tried to convince him to take over and do what was right.
Meanwhile, Jack continually tried to "one-up" Sawyer, and threatened to withhold antibiotics from him, mere days after he'd been shot by Mr. Friendly and was recovering from an infection. After Sawyer took the medical supplies, Jack won them back from him in a poker game. ("Lockdown")
When they learned Henry Gale was not who he said he was, Jack and Kate traveled to the Line to force a trade between the captive Other and Walt. No Others appeared, but, after sunset, they saw Michael running out of the jungle, frightened and wounded. Jack brought him back to the Swan, where he and Kate tended to his wounds. ("S.O.S.")
Determined to regain control, Jack went with Locke and Kate to retrieve the rest of the guns from Sawyer after Michael announced a plan to take on the Others. He pulled a gun on Sawyer and burned the manuscript he'd been reading in an attempt to get him to comply. Sawyer revealed to him how Ana Lucia Cortez had gotten his gun. ("Two for the Road")
They rushed back to the Swan when they learned Ana Lucia was alone at the Swan Station with Michael and Henry. They found Ana dead in the living room. While working to treat the mortally wounded Libby, Jack sent a reluctant Kate to go with Sawyer so she could find out where the stash of guns and heroin were located. ("?")
During Ana Lucia and Libby's funeral, Sun spotted a sailboat approaching the Island. Without hesitation, Jack, Sayid and Sawyer dove into the water, and confronted the owner of the boat. It was revealed to be Desmond, who tried to escape the Island with his boat, yet couldn't find anything but the Island.
Before Jack, Michael, Kate, Sawyer and Hurley started their mission to attack the Others, Sayid recounted to Jack his suspicions about Michael and his plan for Walt's rescue. In addition, Sayid and Jack made a secret plan – Sayid would take Desmond’s boat and use it for a secret flanking maneuver on the Others' camp before Jack and the rescue mission arrived. Later, Michael discovered his gun was not loaded and Jack told him he had forgotten to load it. As the group was walking alongside a small river, Kate spotted two Others stalking them on the other side. She and Sawyer opened fire, killing one of them. Michael got upset at this, whereupon Jack confronted him about his betrayal. Michael was forced to tell the truth, admitting that he had killed Ana Lucia and Libby, let the false Henry Gale go, and led the rescue party upon the Others' instructions, in order to free Walt. They had given him a list with their names on it. Hurley wanted to go back but Jack convinced the skeptical party to continue onward, revealing Sayid's plan.
Later, Jack realized they were not heading to the place Michael had told them about before. Suddenly, the party began to hear whispers, and they were soon ambushed by the Others, who used electrical stun darts and captured their entire party. They woke up at the dock where Henry was revealed to be the leader of the Others. He gave Michael and Walt a boat and a bearing on which they could leave the Island, then sent Hurley back to the beach to tell the other survivors not to come looking for them. Jack, Kate and Sawyer were hooded and told they would be going home with the Others. ("Live Together, Die Alone")
Jack attempted to break out by assaulting Juliet as she was bringing him food. He dragged her out into the corridor of the Hydra and commanded her to open a door, which she said would kill them if opened. He unlatched the door himself and the door burst open, flooding the corridor. Jack and Juliet managed to force the door shut, and Jack was then knocked unconscious by Juliet.
He awoke again in the room and with Juliet looking through a window, sitting at a table outside the room. After Jack decided to cooperate, Juliet revealed that she had a file containing details on Jack's life.("A Tale of Two Cities")
Jack later met Henry, who said his real name was Benjamin Linus and that he had been born on the Island. He then proved that the Others had contact with the outside world by showing Jack news footage of the Boston Red Sox winning the World Series. Jack was then offered a trip home if he cooperated with the Others. ("The Glass Ballerina")
When Colleen was brought back with a gunshot wound, Juliet, unable to stabilize her, demanded that Jack help save her life. While washing up outside the makeshift operating room, Jack saw X-rays on the wall, but was told that they weren't hers. Colleen went into cardiac arrest and Jack could not get a defibrillator so she died. Jack then revealed that he had figured out from the X-rays he saw that he had been brought there to perform a spinal surgery on one of the Others and demanded to know who it was. ("Every Man for Himself")
Despite not knowing, Jack ran a bluff on Ben, asking him about the symptoms associated with the tumor. Ben learned he had been conned by Jack (who was only making an educated guess about the X-Rays). Ben told Jack that he'd had a whole plan to break him and make him want to do the surgery, but that was destroyed when Jack figured out the job the Others wanted him to do. Later, Juliet sneaked a message to him via videotape indicating that Ben was a liar, and suggested Jack kill Ben during the surgery. ("The Cost of Living")
When Ben returned to ask Jack about the surgery, Jack inquired about the operating room and equipment, then scoffed at the idea of performing the operation, saying he didn't trust Ben or the Others. Juliet responded by bringing in Kate, who informed Jack that the Others would kill Sawyer if he didn't operate. Later, Jack got a message over the intercom telling him to try the door. It was unlocked and Jack was able to make his way to a weapons locker where he picked up a pistol, then to a monitoring room where he saw Kate and Sawyer sleeping together.
Ben confronted Jack, and Jack lowered the gun and told Ben he'd do the surgery the next morning, but in return he wanted to get off the Island. Ben agreed and Jack started the operation the next day. During the surgery, Jack deliberately cut Ben's kidney sack. He told the Others that Ben would die unless he repaired the damage, and demanded one of their transceivers. He forced Pickett, who was about to execute Sawyer, to turn his transceiver over to Kate. Jack told her that she had an hour to get away. Kate was reluctant to leave without him, but Jack told her to run. She fled with Sawyer. ("I Do")
Juliet sent Others to find Pickett, and hunt down the escaped prisoners. She authorized the use of deadly force if needed. Jack proceeded to repeat Juliet's hidden video message in front of Tom and a semi-conscious Ben. Jack agreed to give Juliet three minutes alone with Ben, during which Tom formally introduced himself to Jack. After the conversation, Juliet told Jack to finish the surgery and repair the damage to Ben, and that she would help Kate and Sawyer escape. Jack finished the surgery, and heard from Kate that she was safe. He told her not to come back after him.
Jack demanded that Juliet repeat what Ben told her during the three minutes. Juliet confessed she had been on the Island for over 3 years and Ben promised she could finally go home if his life was saved and she helped Kate and Sawyer escape. ("Not in Portland")
Jack was moved to the cage Sawyer had occupied. He refused to help either Juliet or Ben any more. Later that night Isabel came to Jack and took him back inside the station to ask him questions concerning Juliet's desire to see Ben dead. Jack obeyed, but lied on behalf of Juliet.
Jack discovered Juliet had killed Danny to save Sawyer and Kate and was going to be executed. He requested a meeting with Ben, during which he explained that Ben's infection was serious and needed treatment. Jack offered the treatment on the condition that Juliet be allowed to live. Ben agreed, but sent word that Juliet should be marked instead. Later, after being marked, Juliet showed the wound to Jack, who tended to it. Jack was then taken to the Hydra Island shore, where he joined the Others on their return to the Barracks. ("Stranger in a Strange Land")
At some point during his stay at The Barracks, Jack and Ben played chess at Ben's house. Ben expressed his regret that Jack was leaving. He affirmed that he intended to honor their agreement, but suggested that the Island may decide otherwise. Ben also asserted that if Jack left, the day might come that he would want to return again. Jack disagreed and made an aggressive chess move. Ben immediately retaliated with a defensive "castle" move. ("King of the Castle")
After 6 days, Sayid, Kate, Locke and Rousseau found the barracks and saw Jack playing football with Tom. ("Par Avion") That night, Kate was caught when she sneaked into Jack's house. Later, Jack came to see her where she was being held in the barracks' recreational center and told her he had made a deal with Ben to leave the Island and that he planned to come back for her. ("The Man from Tallahassee")
After the Others left the Barracks, Kate found Jack lying unconscious in his house. He woke up and Kate told him that the Others had left. They left the house and found Juliet and Sayid. Sayid told Jack that Juliet could not come with them, but Jack said, "She was left behind too." ("Left Behind")
Jack took Juliet back to the camp and told the survivors she was under his protection. After she apparently cured Claire and gained the survivor's trust, Jack brought her equipment in order to get her started at the beach camp. ("One of Us")
Juliet woke Jack in his tent to have a heart-to-heart talk with him. She told him that his friends' distrust of her was justified; she was still working for Ben in order to let him know which women at the beach camp were pregnant, so he could take them. Jack questioned her motives, as she had wanted to get on the submarine so badly, and Juliet's answer was that she didn't get off; she was still there. She described having seen Sun's baby, and told Jack she was tired of living Ben's dream. ("Operation: Sleeper")
Later, Jack and Juliet were sitting on the beach when Kate approached them, wanting to talk to Jack alone. During the following argument Kate said the survivors no longer trusted Jack and that Desmond, Charlie, Hurley and Jin were concealing Naomi's presence. It also came to light that Jack and Juliet were concealing a secret of their own. Juliet wanted to tell Kate but Jack insisted "Not yet." ("The Brig")
The following night, Jack and Juliet arrived at a beach gathering, where Sayid was giving a speech about his distrust of them both. Jack told his fellow survivors that he knew about Juliet being a mole, and that they were devising a plan to do away with the Others once and for all. ("The Man Behind the Curtain")
Jack revealed to the camp that he, Rousseau, and Juliet had been planning to use dynamite from the Black Rock to lay a trap for the Others. When it was revealed that the Others were coming sooner than expected they decided to evacuate most of the survivors to the radio tower. ("Greatest Hits")Jack set off with the group while three of the survivors remained behind to spring the trap. As night fell, Jack's group could see in the distance that only two out of three sets of dynamite had exploded, and though this led Rose, Sun and some others to want to go back, Jack convinced everyone to continue with the journey.
When they reached the radio tower, Locke appeared and threw a knife which appeared to kill Naomi. Then, though he was being held at gunpoint by John, Jack called Naomi's boat, to the rest of the survivors' delight. A man named Minkowski answered the phone, and told Jack someone was on the way. Jack, relieved, thought he had saved everyone. ("Through the Looking Glass")
Jack and Kate optimistically discussed their imminent rescue and Jack promised to kill Locke if he saw him. Jack answered a call on the sat phone and Minkowski informed him the signal was weak. Jack offered to adjust it, but Minkowski asked for Naomi. Unwilling to reveal Naomi was dead, Jack said she was looking for firewood and ended the call. When he turned around, Naomi was gone. Rousseau found a trail of blood and suggested they follow it, but Kate had found another one and thought Naomi might have been trying to mislead them. Jack said Naomi was hurt and not thinking about trying to trick them. Kate seemed to agree and gave him a hug, then Jack and Rousseau went into the jungle to find Naomi, dragging Ben along with them on a rope.
The trail ended abruptly. Jack reached for the sat phone, but couldn't find it. Ben revealed he had seen Kate take the phone when she hugged Jack but hadn't said anything. They headed back to the cockpit to meet the other survivors, and Jack attacked Locke, knocking him down and taking his gun. He aimed the gun at Locke's head and Locke said Jack wasn't going to shoot him. Jack pulled the trigger, but the gun clicked on an empty chamber. He started to beat him and the other survivors pulled him off.
Locke got to his feet and said anyone who wanted to live should come with him, but Jack said Locke was insane and nobody was going to follow him. Hurley disagreed, citing Charlie's message, and he and Claire sided with Locke. Other castaways joined him, and Jack allowed Ben to go with him as well. Locke's group left for the Barracks and Jack's group headed for the beach.
Alone at the cockpit, Jack and Kate reminisced about Charlie and their trip to find the transceiver. They heard a noise Kate initially mistook for thunder, but Jack recognized it as the sound of a helicopter. They moved into a clearing and saw a helicopter flying erratically, then something dropping from it to the ground. They ran toward it and found a parachutist, who removed his helmet. Upon seeing them, he asked, "Are you Jack?" ("The Beginning of the End")
Jack and Kate introduced themselves and learned the parachutist's name was Daniel Faraday. Jack gave Daniel the sat phone and allowed him to call Minkowski. He became suspicious when Minkowski told Daniel to take him off speaker phone, and even more so when he saw the gun Daniel was carrying. Jack and Kate decided to play things out and help Daniel find his colleagues, who could be tracked by GPS signals on their parachutes. They came upon a metal biohazard box containing gas masks and red bags. Daniel seemed reluctant to answer any questions, but said rescuing the survivors wasn't his team's primary objective.
They followed Daniel as he tracked his fellow team members and eventually found Miles, who accused Jack and his people of killing Naomi. He demanded to be taken to her body and Jack obliged. After kneeling over Naomi's body and whispering mysteriously, Miles accepted Kate's claims that John Locke was the one responsible for her death. He started picking up Charlotte's signal and told everyone to follow him, but Jack refused, saying his people were in the jungle with guns. Miles was doubtful until two shots rang out. Juliet and Sayid emerged from the trees and took the men from the freighter hostage.
The group saw Charlotte's signal and thought it was coming their way, but the beacon had been attached to Vincent. Jack realized Charlotte had been captured by Locke. They found Frank Lapidus and the helicopter, both in good condition. Lapidus found out Juliet hadn't been on the plane and told Miles she was a native. Miles aggressively demanded to be taken to Ben, but Jack intervened to protect Juliet. ("Confirmed Dead")
Sayid showed Jack a picture of Desmond and Penny, which he had found on Naomi's body. Jack asked Juliet to go to the beach to get Desmond. Sayid decided to go to the Barracks to reclaim Charlotte and told Jack not to go with him. Jack told Kate to go instead, telling her Sawyer would protect her from Locke. Alone with Daniel and Frank, Jack watched as Daniel performed a series of experiments. When Sayid and Charlotte returned without Kate, Jack was visibly hurt that she had decided to stay at the Barracks. ("The Economist")
Desmond and Sayid loaded Naomi's body onto the helicopter and left for the freighter with Frank. Jack and Juliet took Charlotte and Daniel to the beach. Sun asked him if Locke could be correct about the freighter team's intentions, and when Jack denied that possibility asked why Kate had stayed with him if that were the case. Jack tried to contact the freighter with the sat phone, then asked Charlotte to try to use an emergency line. When she finally got in touch with Regina, she was informed the helicopter hadn't arrived yet. ("Eggtown")
Confused, Jack asked Charlotte how it was possible that the helicopter had not reached the freighter yet. When Juliet observed that Charlotte didn't seem worried, Daniel told them time on the Island may move differently than off the Island. He reassured them that everything would be fine as long as Frank followed the bearing Daniel had given him. If he didn't, there might be side effects. Some time later, Sayid finally phoned from the freighter and informed him Desmond was acting strange. Daniel told Jack some people could get confused going to and from the Island. Jack let him speak to Desmond and give him instructions. ("The Constant")
Later that night, Jack discovered Daniel and Charlotte had disappeared. Jin revealed he had seen them go into the jungle but didn't think to tell anyone since Jack had said they were friends. Jack, Juliet, Sun and Jin went into the jungle in different directions with torches. Jack came across Juliet, who was having a heated conversation with a woman named Harper. Harper suggested Jack go with Juliet to stop Daniel and Charlotte, then disappeared into the jungle. Juliet told him Harper, who had been her therapist, said they were heading for the Tempest, but was reluctant to give him more information. The next day, Jack and Juliet found Kate, who told them Charlotte had knocked her out. While Jack tended to her wound Juliet left to continue the search alone. Kate helped Jack find the Tempest and told him why she had stayed at the Barracks. They arrived at the Tempest just as Juliet and Charlotte emerged from the station. Kate was skeptical when Charlotte claimed she and Daniel had just saved the lives of everyone on the Island and Charlotte took her inside to see for herself. Jack stayed outside with Juliet, who said Ben had sent Harper the night before with instructions to kill Daniel and Charlotte. She told Jack Ben would win the war that was coming, and when he did Jack needed to be away from her because Ben thought she belonged to him. Jack kissed her tenderly and said, "He knows where to find me." ("The Other Woman")
Jack, Juliet, Kate, Charlotte and Daniel had all made it back to the beach the following morning. While preparing breakfast, Jack noticed Jin's growing English vocabulary. Jin informed Jack that both Sun and Sawyer had been teaching him English and pointed out that Sun was much better. Sun approached the two men which triggered Jack to ask about how Sun was feeling. With a fake smile, Sun assured Jack that everything was fine and that the morning sickness had subsided. ("Ji Yeon")
In his tent, Jack looked through some pills for a stomach ache. Kate came in and they talked for a while until Bernard started yelling on the beach. Jack and Kate ran over to find a body laying in the water. Faraday told them it was the doctor from the freighter. Jack then made Faraday hurry up fixing the phone. Later that night Faraday used Morse Code to communicate with the freighter and lied to Jack about what he was told. However, since Bernard knew Morse Code, he called out Daniel's lie, revealing what the real message said, that the doctor was fine. Jack grabbed Faraday by the collar and asked if they were ever planning on taking the survivors off the island. When Faraday said they weren't, Jack's stomach began to act up again and he walked away in pain. ("The Shape of Things to Come")
With Juliet's input, Jack concluded he was suffering from appendicitis and needed immediate removal of his appendix before it ruptured and killed him. While doubtful of Juliet's expertise in surgery, Jack demanded to be kept awake during the procedure to oversee and help. However, the pain proved to be too great for him, and Bernard knocked him out with chloroform at Juliet's command. The surgery went well and Jack woke up just in time to hear Juliet say she thought Jack really loved Kate. After Kate left, Juliet stated she knew Jack was awake. ("Something Nice Back Home")
After his surgery, he left the tent against Juliet's orders and went to the pantry to eat. Juliet was upset at this, but Jack calmed her. They heard the helicopter coming, and went out to the beach. As the helicopter passed over, a backpack was dropped containing papers and a satellite phone wrapped in cloth. Jack then stated that he thought "they want us to follow them." ("Cabin Fever")
Kate and Jack, both armed, followed the helicopter through the jungle, tracking it with the sat phone. After hiking what appeared to be all night, they ran into Sawyer, Miles, and Aaron making their way back to the beach from the Barracks. Kate took Aaron, and she and Miles returned to the beach while Jack and Sawyer continued on toward the chopper. They arrived at the chopper and found Frank alone, hand-cuffed to a seat. He told them where Keamy and his team were going, and warned them of the danger of the Orchid. Frank promised to fly them off the Island right away, but Sawyer remembered Hurley was with Locke and Ben and therefore in danger. Jack and Sawyer went back into the jungle, in search of the Orchid, to save Hurley's life. ("There's No Place Like Home, Part 1")
Jack and Sawyer arrived at the Orchid and found Hurley and Locke. In the Orchid greenhouse, Locke told Jack not to leave the island and that if he had to, to lie about everything that had happened. Jack left after Locke and Ben entered the Orchid elevator. Jack, Sawyer and Hurley went back to the chopper and met Kate, Sayid, and Frank. They lifted off and started toward the ship. Jack told Frank not to go back to the island when there was a fuel leak. When the chopper landed on the freighter, Jack made sure they left quickly and brought Kate back when she started to go after Jin, who was still on the freighter. The chopper left with Sun, Aaron and Desmond right before the freighter blew up. The chopper lost fuel quickly and fell into the sea after the Island had disappeared. Jack resuscitated Desmond when they got in the life raft. When they were found by the Searcher, Jack instructed the others that they had to lie about everything that had happened since they arrived on the island. One week after being rescued by the Searcher, Jack said his goodbyes to Frank and Desmond, telling the latter he would "see him in another life." He departed with the others for the island of Sumba. Approximately eight or nine hours later, after paddling with a piece of wood, they arrived and were discovered by the native inhabitants, who informed the US Coast Guard that survivors from Oceanic Flight 815 had been found. ("There's No Place Like Home, Parts 2 & 3")
On board the US Coast Guard plane, Jack told Karen Decker that the Oceanic 6 would talk to the press. Upon landing in Hawaii, he was greeted by his mother. He took part in the press conference in which the Oceanic 6 lied to the public about how they survived the plane crash. He described the majority of the fabricated story to the press including the plane crashing into the water and the deaths of the other survivors.
Over 6 months after their rescue, Jack held a wake for his father. After the wake, Carole Littleton approached Jack and told him her daughter, Claire, had been on Jack's plane and was his half-sister. Carole then complimented Kate's baby, not realizing Aaron was her own grandson. ("There's No Place Like Home, Part 1")
Jack poured himself a screwdriver while watching a story on the morning news about a Camaro being pursued by the police. He recognized the car as belonging to Hurley, and later went to the mental institution to visit him.
Hurley accused Jack of checking up on him to make sure he hadn't revealed the Oceanic 6's secret. He insisted they must go back to the Island, an idea that Jack disagreed with. Hurley also apologized to Jack for following Locke on the island. ("The Beginning of the End")
Sometime after this, Jack testified during Kate's trial, saying there were only eight people who survived the crash, and that two of those eight died. He claimed to have never met the marshal and denied his love for Kate.
He met Kate after the trial and told her he had lied, implying that he really did love her. He didn't want to come back with her to her house, and Kate gathered that this was because of Aaron. Jack asked her if she wanted to get coffee instead, but she declined and told him she would only start seeing him when he could be around Aaron. ("Eggtown")
At some point Jack came to terms with Kate raising his nephew and he and Kate became seriously involved. He moved into Kate's house and acted as a father figure for Aaron, but his insecurities forced him to compare himself to his own father. Jack maintained contact with Hurley and was called in when Hurley stopped taking his medication. Hurley told Jack he had a message from Charlie: "You're not supposed to raise him." Jack was initially dismissive until Hurley continued, saying Charlie said someone would be visiting Jack soon. ("Something Nice Back Home")
Jack proposed to Kate, and she happily accepted. Later, while working late in the hospital, Jack saw his father for the second time since leaving the Island, and this time Christian spoke to him. Startled by another doctor, Jack asked for a prescription for stress-relieving medication. Jack went home, found Kate talking on the phone, and was suspicious of who she was talking to, even more so after she gave him a name he didn't recognize. Soon after, Jack came home early and found their nanny still there, and Kate not yet home. When Kate did come home much later, Jack, now intoxicated, demanded to know where she was. Kate tried to insist that Jack trust her, but he lost control when Sawyer's name was mentioned. While he reiterated how it was Jack who "saved her," Kate finally told him to seek help, as she didn't want him acting like this around her "son." Jack yelled back that she wasn't "even related to him," when Aaron appeared in the doorway. Kate went to the boy, and Jack left. ("Something Nice Back Home")
Sometime after these events, John Locke appeared to Jack under the alias Jeremy Bentham. Locke explained to Jack that horrible things had occurred on the Island and that they were Jack's fault. This conversation took place after Locke's car accident. Locke tells Jack that Christian Shephard was the one who told him to move the island, which causes Jack to become furious. That conversation had a strong impact on Jack and drove him into a depression. ("The Life and Death of Jeremy Bentham")
Afterwards, Jack spent most of his time drinking, examining maps and geography books, and using the golden pass given to him by Oceanic Airlines to fly back and forth across the Pacific Ocean. He hoped one of the planes he got onto would crash, either returning him to the Island or killing him. ("Through the Looking Glass")
On one of these trips, while flying back to L.A., Jack read a newspaper article that deeply upset him and caused him to later call Kate. She did not answer, and Jack, in his distraught state, contemplated leaping from a bridge near L.A. At that moment, a young woman, distracted by the sight of Jack about to jump, crashed her car on the bridge, and Jack was forced to postpone his suicide attempt and rescue the passengers.
Later, after successfully rescuing the family that crashed, Jack was visited by Sarah, now pregnant and re-married. She tried to make sure that Jack was okay, then left, noting that she had come only because she was still Jack's emergency contact. Jack asked for a ride home, but Sarah explained that it would be "inappropriate" for them to ride in the same car.
An obviously unwell and still distraught Jack asked Dr. Hamill to allow him to perform the surgery on the survivor of the car crash, who had suffered a spinal injury. Dr. Hamill refused, telling Jack he had earned a rest and calling him "a hero twice over."
Jack visited the Hoffs/Drawler Funeral Home to attend the funeral services for Jeremy Bentham, the person mentioned in the newspaper article. Seeing that no one else was there, Jack asked if he had missed the funeral. The funeral director explained there had not been a funeral, only a viewing, and Jack was the only one who had come. When asked whether he was friend or family to the deceased, Jack replied, "Neither."
After failing to get more painkillers by impersonating his father at a pharmacy, Jack went to the hospital to steal drugs. Dr. Hamill confronted Jack about his problems, and Jack lashed back, asking him to get his father "down here" and see which of them was more drunk.
Finally, Jack managed to reach Kate and asked to see her. Jack drove to the airport moments before Kate arrived. Kate remarked on his deeds at the bridge, but soon expressed her reluctance to be there. Jack showed Kate the article he saw in the paper and then told her what his life has been like since leaving her. Kate explained that she had to leave before "he" started wondering where she was, and began to walk away. Jack then started shouting that they "have to go back." ("Through the Looking Glass")
Kate condemned Jack for wanting to go back to the Island and for showing her the obituary for Jeremy Bentham when he couldn't even be there for her and Aaron. Jack tried to calm her down, but she refused to listen. She got back in the car and sped away. ("There's No Place Like Home, Parts 2 & 3")
Jack drove back to the funeral home and found it had closed for the day and the front door was locked. He broke inside to see Bentham's body and was shocked to find he was not alone. Benjamin Linus was also there. Ben explained to Jack that if he ever wanted to return to the Island he would have to convince everyone else who left the island to return also, including the man in the coffin: John Locke. ("There's No Place Like Home, Parts 2 & 3")
After Ben and Jack removed the coffin from the funeral home, they went to a hotel where Jack shaved his beard off and they discussed their plans to gather the rest of the Oceanic Six. Ben asked Jack if Locke told him what happened on the Island after it moved, to which Jack replied, "No, he didn't." Jack saw the news report on the hotel TV about Hurley's escape from Santa Rosa and apparent murder(s). ("Because You Left")
While in the hotel room, Ben disposed of Jack's pills by flushing them down the toilet. Ben explained that he should go home and pack a suitcase of anything he wanted in "this life," because he is never coming back. A little later, Hurley contacts Jack and arranges for him to meet with his father. Hurley's father took Sayid's unconscious body to him, where Jack took him to St. Sebastian Hospital for treatment. At the hospital, Jack called Ben to inform him about Sayid. Jack successfully treated Sayid and managed to get him to wake up. ("The Lie")
Jack was checking over Sayid when the Chief of Clinical Services called Jack out of the room and reminded him he has been suspended from the hospital because of substance abuse. Jack's phone rings and it's Hurley. Hurley told Jack he is happy and asks how Sayid is. Jack told him Sayid is fine and Hurley told Jack to tell Sayid that he followed his advice not to trust Ben. Ben arrived and he and Jack returned to Sayid who had just shot a nurse with darts. Jack watched as Sayid checks the fake nurse's wallet and finds an address written on a scrap of paper. Jack told Sayid that it was Kate's address.
Jack called Kate and persuaded her to tell him where she is because he wants to see her. Ben told Jack that after he gets Kate to meet him at slip 23 at Long Beach Marina.
Jack met with Kate and she told him that someone knows that she is not Aaron's mother and a lawyer, Dan Norton, came to try and take her blood. They saw Dan driving off in his car so Jack gets into the car with Kate and they chased after him.
Jack and Kate followed Dan to a motel where they see he is meeting with Carole Littleton, Claire's mother. Jack told Kate he will persuade Carole that they lied for Aaron's own good and goes to her room. Jack told her that he and Kate lied for Aaron's sake but Carole is confused and asks, "Who's Aaron?" Jack realized that she is not Dan Norton's client. Jack gets back in Kate's car and told her that Carole is only trying to settle a lawsuit with Oceanic Airlines and doesn't know who Aaron is. They drove off to meet with Ben, unbeknownst to Kate.
A while later, Jack and Kate get to the meet. Jack told her Ben is here to help them when Kate is startled to see him. Jack defended Ben when Kate says he is the one who is trying to take Aaron until Ben told him that this is indeed true and apologized to Jack. ("The Little Prince")
Angry of the deception, Kate hastily left, and Sayid followed. Ben managed to convince Sun that her husband is alive, and Ben drove Jack and Sun to a church in LA, where they coincidentally met Desmond, who came looking for Daniel Faraday's mother. They go into the church to find Eloise Hawking, who is revealed to be working with Ben to rejoin the Oceanic 6 and is Daniel's mother. ("This Place Is Death")
Eloise showed the group the Lamp Post, the first DHARMA station, built to find the Island. After explaining the properties of the Island and it's future location in time, she ordered to Jack that the Oceanic 6 needed to take Ajira Airways Flight 316 to Guam, which would go through a window and transport them to the Island. She privately talked to Jack. She gave him Jeremy Bentham's suicide note, and told him that he needed to find something that belonged to Jack's father and give it to John.
While in a bar, Jack received a call that his grandfather attempted to escape his retirement home. He discovered that his grandfather was given belongings that once belonged to Christian Shephard, including a pair of shoes. Jack is allowed to take them.
Later at his house, he found Kate on his bed. She agreed to come with him to the Island on the condition he never asked about Aaron, and then they kissed. The next morning, Jack received a phone call from Ben explaining that he had been sidetracked and that Jack had to pick up Locke's coffin. Jack went to Simon's Butcher Shop, and Jill let him into the back room where Locke's coffin was being held. He swapped Locke's shoes for the pair which belonged to his father. He also put the unopened suicide note inside to coffin. Jack then went to the airport and spotted Kate while he was checking the coffin onto the plane. Caesar offered his condolences to Jack over the loss of his "friend." Jack met up with Sun, and they both witnessed Sayid being escorted by Ilana. Later, he met Hurley, who bought most of the seats on Flight 316 in order to protect everyone about to get on the flight from going to the Island.
Shortly before takeoff, one of the air hostesses handed Jack the suicide note he had put inside Locke's coffin. Once the flight had taken off, he found out that Frank Lapidus was piloting the flight. Frank noticed that five of the Oceanic Six were on board the flight, asking Jack that they're obviously "not going to Guam, are we?"
Further on the flight's journey, he read John Locke's suicide letter. It read, "Jack, I wish you had believed me. JL." The flight suddenly encountered heavy turbulence, and was then surrounded by a bright light. ("316")
After the crash of Flight 316, Jack woke up in the middle of the jungle, as he did when he first crashed on the Island. He found Hurley and Kate at the waterfall, with the rest of the passengers nowhere to be seen. Jack, Hurley and Kate heard music nearby and spotted a DHARMA van coming to the side of the lagoon. The van stopped, and Jin (wearing a DHARMA suit) stepped out with his rifle. Jin called Sawyer as he transported the three to a meeting ground where they were reunited. ("316") ("LaFleur")
Jack along with Hurley and Kate were integrated through posing as new recruits to the DHARMA Initiative as a workman through help from Sawyer and Juliet. His processing into the DI was completed by Pierre Chang at the Processing Center, as Amy was recovering from the recent birth of her son, Ethan. Jack faced some trouble when processing and had to think on his feet when answering Chang's question. Having been introduced to the Initiative, Jack settled into his new home and, that night, went to find Jim LaFleur's house and discovered Sawyer and Juliet were living together. After sharing a warm welcome with Juliet, Jack had a conversation with Sawyer in which he acknowledged that Sawyer was in charge now, and he would have to take a back seat. ("Namaste")
Jack, Kate, and Hurley had lunch at the Barracks cafeteria. Hurley tells Kate that Juliet and Sawyer are 'together'. Later on, when a DHARMA van crashed into a house, Jack helped to put out the fire with a fire hose. ("He's Our You")
After the fire was put out, Horace briefed the gathered DHARMA personnel on the prisoner's escape. When Jack questioned how Sayid could have started the fire when he was locked up, Horace regarded him suspiciously. After a janitor's set of keys were found in the lock of the holding cell Jack became a suspect and was placed under house arrest (along with Kate and Hurley) by Sawyer, to avoid any complication.
Sawyer tried to recruit help on little Ben's surgery, but Jack refused. He told Kate that he already saved Ben's life once, and that he did it for her. He claimed that he's done trying to fix things and now puts his trust in the Island. When Kate said that she didn't like the new Jack, he said she didn't like the old him either. Later, when getting out of the shower, Juliet burst into the house and confronted Jack for refusing to help Ben. She asked why he came back, saying he didn't need to come back to save them, because they were doing fine without. Jack simply responded that he was supposed to come back for a reason, but he didn't know why yet. ("Whatever Happened, Happened")
Jack covered Roger's work for him, assuming Roger would want the time off because Ben was injured. Roger brushed off Jack's help, and confronted him about Kate's interference. Jack defended Kate, then went to Juliet and Sawyer's house and informed them of Roger's suspicions. ("Some Like It Hoth")
Early the next morning, Daniel Faraday showed up at Jack's house and frantically questioned him on how he returned to the Island. Jack told him about the plane, and about how Daniel's mother, Eloise Hawking, persuaded him to go back. When asked if Eloise spoke about destiny, Jack said yes. Daniel told Jack that his mother was wrong, and that Jack does not belong there. Subsequently, he went to Sawyer's house and informed him of Daniel's return and his departure to the Orchid. Sawyer then showed Jack his own predicament - Phil, tied up in the closet, having discovered Sawyer and Kate took Ben to the Hostiles. Later Jack, Kate, Sawyer, Juliet, Jin, and Hurley all met in Sawyer and Juliet's home to discuss their options. Sawyer suggested either leaving the Island by submarine or heading into the jungle to "start from square one." The group was interrupted when Miles and Daniel arrived asking where he can find the Hostiles so he can find his mother. When Sawyer refused to help, Jack enlisted Kate's help in taking Daniel to the Hostiles' camp. Sawyer argued that Jack was making a mistake and that he, Jin, Hurley, and Juliet would meet them at the beach when their plan inevitably failed.Jack, Kate, and Daniel went to the motor pool to arm themselves but were interrupted by Radzinsky and two other DHARMA workers. When Radzinsky saw their weapons, he accused Daniel of lying about the group's intentions, and a firefight ensued. Jack covered them as they made their way to the jeep and opened fire on a fuel tank, causing a tremendous explosion allowing their escape. When they arrived at the sonar fence, Jack treated Daniel's neck wound as Kate entered the code provided by Juliet. Daniel reminded Jack that 1977 was now "their present," they would do well to remember that they were still at risk of injury or death regardless of their presence in the future. When Jack, Daniel, and Kate stopped at a creek to rest, Jack asked Daniel to explain his intentions. Daniel revealed his knowledge of the impending disaster caused by a massive energy release at the Swan station.
Jack and Kate discussed their options while hiding behind bushes at the Hostiles' camp when suddenly, a gunshot was heard, and they watched Daniel collapse to the ground. As they were about to run away, they were surrounded by Charles Widmore and another Hostile riding horses. Widmore knocked out Jack with his rifle's butt and the other aimed at Kate. They are brought by Widmore into the camp where Eloise ordered that they be taken to her tent. She assured them she'd believe whatever they said because she just killed her future son. Jack told Ellie of Daniel's plan and that by using the bomb, they could alter the future and undo what Ellie did to her future son.
Jack, and Kate are led by Eloise, Richard, and Erik to the bomb. They arrived at the creek where they are supposed to swim under to the tunnels. Kate didn't want any part of this and told Jack she's going back. Erik threatened to shoot Kate if she tried to leave but Sayid came out of the bushes and shot Erik. Jack filled Sayid in about their plan to change the future and little Ben's fate. Kate left and Sayid agreed to help. Richard, Jack, Eloise and Sayid swam down to the underground tunnels beneath the Barracks where the bomb was hidden. When Sayid questioned if Eloise's motives were to really help them or just to "annihilate the Dharma Initiative," Jack responded that her motivation could be trusted because she would be the one to tell them how to get back to the island 30 years from then, but Sayid was not convinced. They came to a room and Eloise uncovered the bomb. She looked at Jack and said "Now what?" ("Follow the Leader")
After reading through Daniel's journal, Sayid realized that they could extract the thermonuclear core of the Jughead, and bring it to the Swan site with relative ease. Jack helped him remove the core, and afterward they followed Richard and Eloise to a concrete wall which Richard broke down revealing the basement of Horace Goodspeed's house. After Sayid donned Horace's DHARMA jumpsuit, he and Jack walked out into the barracks where Roger Linus recognized Sayid as the man that shot his son, and proceeded to shoot Sayid in the stomach. A firefight ensued in which Jack shot and presumably killed three DHARMA Initiative members before a van holding Hurley, Jin, and Miles arrived and saved them, driving to safety. Jack instructed Hurley to drive the van to the Swan while he furiously attempted to treat Sayid's bullet wound. While he treated him, Sayid informed Jack that he could rewire the bomb to detonate on impact, after which the van stopped suddenly, revealing Kate, Sawyer, and Juliet standing in the road ahead of them. ("The Incident, Parts 1 & 2")
Sawyer asked for a minute of Jack's time, and they walked away from the rest of the group to talk. Jack and Sawyer reasoned with one another, Jack attempting to convince Sawyer that they needed to detonate the bomb, and Sawyer attempting to convince Jack that there was no need to change the past, and that what was done, was done. When it became clear that Jack would not yield to this way of thinking, Sawyer punched him, and a furious fight ensued, only ended by Juliet demanding Sawyer stop after Jack was brutally beaten. Jack walked a short distance to a ridge overlooking the Swan site, where he was met by Kate, who tended to his wounds. Jack asked her why she agreed to come back to the Island, and why she left Aaron behind. Kate revealed to him her intentions were to return to the island to reunite Aaron with his mother, and when Jack asked if she would support his plan to detonate the bomb, she agreed.
After returning to the van and retrieving the bomb core from Sayid, he set off alone to the Swan site, where a group of Security team members had just arrived. He was spotted by Phil, however, and was nearly overwhelmed when the rest of the group arrived in the van and helped him attack the site. Jack shot a presumably killed another member, and he and the others successfully killed or neutralized all the DHARMA members present, and after a reaffirming look from Kate, Jack dropped the bomb into the Swan drilling shaft. Initially nothing happened, but after a moment a severe electromagnetic Incident occurred, and all metal objects in the area began to be pulled to the shaft, including a tool box which hit Jack in the back of the head, rendering him unconscious. After a moment, Jack awoke to find Kate desperately attempting to pull Sawyer away from the drilling shaft, which Juliet had just fallen down. Jack helped pull Sawyer away from the shaft, and moments later the bomb presumably detonated. ("The Incident, Parts 1 & 2")
Jack is woken by Kate, feet from an unconscious Sawyer, and the remains of the detonated hatch. He asks where they are, but Kate doesn't have a good answer. Sawyer wakes up and launches himself at Jack, kicking him into the crater of the hatch and agonizing over Jack's failure and Juliet's death. Kate tries to keep Sawyer away, and Jack apologizes, thinking that he failed.
After retrieving Juliet's body from the wreckage of the hatch, Jack checks on Sayid and realizes he can't help him. When Hurley suggests taking Sayid to The Temple, based on mysterious circumstances, Jack uncharacteristically doesn't question the idea. The group enters the Temple, all of their names having appeared on one of Jacob's lists.
When the attempt to save Sayid's life in the healing pool fails, Jack tries giving emergency CPR to his friend. When Kate tells him to stop, he does ("LA X, Parts 1 & 2").
On Oceanic flight 815, Jack was very nervous. When he saw Rose he was scared that something happened on the plane. She said that she was waiting for her husband. When Jack entered the lavatory, he found that his neck was bleeding. Jack returned to his seat and met Desmond, whom he seemed to recognize. Desmond did not seem to recognize Jack, and it is unclear as to whether they previously met at the stadium in this alternate timeline.
Later, he returns to a lavatory, where he finds a man waiting for his "friend". The door opens and a woman stumbles on top of him. They smile at each other as they disentangle, and Jack watches her as she walks to her seat, looking away when he sees the man possessively holding her elbow.
After returning to his seat, a stewardess makes a call over the intercom, looking for a doctor. Jack answers her call and together they go to a lavatory towards the rear of the plane, where a man has been locked inside for half an hour, arousing the alarm of the flight staff. When the door cannot be opened, a stranger kicks the door in, revealing an unconscious man seated upright. Jack and Sayid Jarrah attempt to resuscitate Charlie Pace with the first aid kit aboard the plane, but their efforts fail until Jack is able to remove a small plastic bag of heroin from where it was lodged in Charlie's throat. Charlie is less than thankful, stating that he was "supposed to die." During the fray, Jack realizes that he has lost his pen, which was actually stolen by Kate when they bumped into each other briefly on the plane. ("LA X, Parts 1 & 2")
Jack doesn't disembark the plane immediately, after receiving a hateful glare from Charlie Pace, who is being escorted off the plane by police officers. Among the two passengers still left onboard, Jack sees John Locke as he is transferred to the airport's wheelchair.
While waiting in line for the customs process, Jack hears his name being paged over the airport intercom. He goes to the nearest service desk, only to learn that his father's coffin did not make it onto the plane, and Oceanic Airlines is not sure where the body is. Jack speaks to his mother on the phone, realizing that the funeral they had scheduled for two hours after Flight 815's landing will have to be postponed.
In the office for missing luggage, Jack meets John Locke, whose suitcase full of knives has likewise gone missing. Locke is able to offer Jack comfort, saying that Oceanic didn't lose Jack's father, but they only lost his body. Somewhat calmed by this, Jack asks about Locke's paraplegic status. When Locke tells him his condition is irreversible, Jack asserts that "nothing is irreversible." Before separating, Jack gives John Locke his business card, saying that if he was ever in need of a consult his medical treatment would be "on the house." ("LA X, Parts 1 & 2")