Little is known about Desmond Hume's early life, save for the fact that he was unable to finish university as he had to look after his three brothers after something happened to their father. However, Desmond did work as a set designer for the Royal Shakespeare Company in this period of his life.
Around 1989, Desmond began a six-year-long relationship with a woman named Ruth and the two became engaged. A week before the wedding, Desmond had second thoughts about marrying Ruth. His fears drove him to drink heavily and he woke up in the street, finding himself being helped up by a monk. Desmond believed this was a sign from God for a greater calling and decided to leave everything behind that mattered to him, not even notifying Ruth about his decision, and joined the monk's abbey. The head monk, Brother Campbell, didn't believe Desmond would make it, but was proved wrong by Desmond persistence. Desmond helped the monks bottle their famous and very rare wine, but Ruth's brother eventually tracked him down and Desmond was forced to explain himself to Ruth. Ruth didn't believe Desmond's explanation, telling him he should fess up to being scared the next time he broke up with a girl. After facing Ruth, Desmond turned back to alcohol and got himself drunk on the abbey's wine. Brother Campbell found and promptly fired him, telling him God has different plans for him. He offered to have one of the monks drive Desmond into town if he helped move some of the wine for a customer. Agreeing to Brother Campbell's offer, Desmond met the customer, Penelope Widmore, and the two hit if off.
Desmond and Penny dated for two years. Penny came from a family of great wealth and prestige, whereas Desmond was of much more modest means. This disparity bothered him, yet was of no concern to her, who more than willing to move into Desmond's flat when Desmond was too proud to live in her more expensive flat. But Desmond loved Penny and finally decided to ask her father, Charles, owner of Widmore Industries, for his permission to marry Penny. Charles Widmore was impressed by Desmond's gesture, but made it clear in no uncertain terms, that Desmond would never be a great man and not worthy of marrying his daughter. Desmond was crushed by this statement, but Penny didn't care what her father thought as she loved Desmond and knew he was a good man. Despite her unconditional love, Desmond had second thoughts while buying an engagement ring for her and a few hours later, broke up with her under the pretence that she deserved better than what he offered her.
After breaking things off with Penny, Desmond joined the Royal Scots of Her Majesty's Armed Forces in 1996 and trained at a military camp just outside of Glasgow, Scotland. It was at this camp that his consciousness began to slingshot back and forth from 1996 to 2004. After receiving instructions from Daniel Faraday, a theoretical physicist, Desmond traveled to Oxford University to meet Daniel in 1996 who was a professor at the institution. There he learned his unconsciousness had become "unstuck" in time and he had to find his constant, something he cared for deeply that existed and could find in both time periods; if he couldn't find the constant, then he would eventually die. For Desmond, this constant was Penny. However, she had disconnected her phone number and moved, forcing Desmond to ask her father for help in finding her. Widmore believed his daughter hated Desmond and so gave Desmond her new address so Desmond could hear it from her himself. He found her and eventually got her new number, pleading to her not to change it and to be at the phone on December 24, 2004. He promised he wouldn't try to contact her until that time.
Desmond later rose to the rank of lance corporal in the Royal Scots, but was court-martialed and sent to a military prison for disobeying orders. He left the last book he ever wanted to read, "Our Mutual Friend" by Charles Dickens, in the custody of the prison guards. Immediately upon his release, he was met by Charles Widmore. Charles Widmore revealed that he had intercepted all the letters Desmond wrote to Penny while imprisoned, so she thought Desmond had forsaken her, and Penny was now engaged to another man. Charles offered Desmond a great deal of money on the condition that he never contact her again.
Desmond refused the money and later ended up in Los Angeles, where he was to train in preparation for a solo sailboat race around the world sponsored by Charles Widmore. However, he didn't have a boat, a major setback for a sailing race. Desmond met Libby when she paid for his coffee. He jokingly asked her if she had forty-two thousand more dollars. Curious as to why he would need that much money, Libby learned that he needed a boat to enter Widmore's race and win, so he could get Penny back. Libby told Desmond that her husband David had bought her a boat (naming it Elizabeth, after her), but he had died. Even though she had only known him for a few minutes, Libby was touched by what Desmond wanted to accomplish and gave him her boat.
During his training, Desmond was tracked down by Penny at a stadium. He was surprised that she managed to find him, but she said that with enough money and dedication you can find anyone. She asked him why he hadn't written to her when he was in prison, but he didn't answer. He asked her when she was getting married, but she said that no date had been set. Desmond told her that he was going to win the race and be back in a year. He said he was racing to regain his honor, and the two parted ways. A few minutes later, Jack Shephard was doing a 'tour de stade' of the stadium when he hurt his ankle and Desmond came over to assist him. Asked why he was running, Jack told Desmond about a promise he made to fix a patient, but he couldn't keep that promise. In response, Desmond asked him what if he did fix her. When Jack returned to the hospital, he discovered Sarah was fixed.
On the Island
During the sailing race, Desmond's boat encountered a severe storm and shipwrecked on the island about three years before the crash of Oceanic Flight 815. A stranger clad in a biohazard suit, Kelvin Inman, found Desmond and carried his unconscious body to The Swan. When Desmond regained consciousness, he was told he was found washed ashore with no sign of his sailboat. He learned that Kelvin's job in The DHARMA Initiative station was to enter a code into a computer every 108 minutes, and so it became Desmond's job, too.
Desmond watched the station's orientation film many times, noting that pieces of the film were missing. Kelvin told him that his former partner, Radzinsky, had made some edits. Radzinsky had also figured out how to fake a lock down of the station and how to create an invisible map on one of The Swan's blast doors. After pressing Kelvin for more information on Radzinsky, Desmond learned that the man had put a shotgun in his mouth and killed himself.
Kelvin presumably left the station to retrieve supplies from the periodic resupply drops and to survey the island for the invisible map, but Kelvin refused to allow Desmond out of the station. He informed Desmond of a quarantine outside which necessitated the use of the biohazard suit and the need to inject themselves with a vaccine every nine days. In addition to the quarantine, there were a group of hostiles outside on the island - the Others. And so Desmond was left cooped up inside The Swan, but cabin fever also affected Kelvin as Desmond found the man drunk in the crawlspace underneath the station. Desmond learned that the "incident" involving the station was due to a leak of geologically unique electromagnetism, and so a charge builds up and the entry of the code every 108 minutes discharges it before it gets too big. Kelvin showed him a system termination key that activated a fail-safe device, likening its use to pulling a finger out of a dam and blowing it up instead.
Three years after shipwrecking on the island, Desmond noticed a tear in Kelvin's biohazard suit when Kelvin left the station. Suspicious of his partner, he followed Kelvin to a lagoon and discovered his sailboat moored there. Desmond confronted his partner and learned Kelvin was only a week away from finishing repairs on the sailboat, but Kelvin needed Desmond to remain in The Swan to keep pushing the button after he left. Fed up with pushing the button and believing it may not even be real, Kelvin offered to take Desmond with him, but Desmond was furious at being exploited and accidentally cracked Kelvin's head on some rocks. Desmond retrieved the fail-safe key from Kelvin's body and hurried back to the station where he discovered the timer had reached zero and a system failure was in progress. Desmond managed to enter the code into the computer and discharge the electromagnetic buildup, but the damage was already done. Unbeknownst to him, Desmond's failure to enter the code in time had brought Oceanic Flight 815 crashing down upon the island.
With Kelvin dead, Desmond was left alone inside the station with the solemn duty of entering the code every 108 minutes. He began to lose all hope of ever returning home, of ever seeing Penny again or another living person. However, above his head, two survivors of Oceanic Flight 815 - John Locke and Boone Carlyle - had discovered and unearthed a hatch leading into the station. Inside the station, Desmond contemplated suicide and opened the last book he ever wanted to read, but discovered a letter Penny had put inside. She knew he would turn to that book when he lost all hope, and so the letter told him not to give up and that all they needed was each other. She would wait for him, always. In his anguish, Desmond trashed the bookshelves, but then he heard pounding coming from the hatch. Above ground, Locke pounded away on the hatch in anguish after Boone was fatally injured while trying to find a way inside. Desmond turned on a floodlight to see the figure of a person above ground, while Locke witnessed a bright light emanating from the hatch. The sight filled both men with hope.
Locke eventually succeeded in opening the hatch with dynamite procured from the Black Rock. Kate was the first to descend inside The Swan and Desmond captured her. Locke came down after her and was met by Desmond, who initially believed he was Kelvin or Radzinsky's replacement. After Locke failed to give him the proper response to a coded question, Desmond held him hostage. Remembering how Kelvin told him that pushing the button saves the world and that he missed a push, Desmond asked Locke if the world was still out there. He learned that it was and that Locke and Kate were survivors of a plane crash. Kate eventually managed to get the drop on him, and Desmond accidentally shot the computer responsible for entering the code. He attempted to repair it, but upon powering up the computer the power transformer blew. In a state of panic, Desmond grabbed some food, medicine and injector, and fled the station. Jack followed him and Desmond gave him the code, should Sayid be able to repair the computer.
Desmond disappeared into the jungle, leaving not enough of a trail for even Locke to follow. He completed the week's worth of repairs to his sailboat and set sail due west. Desmond sailed for two and a half weeks at a speed of six knots, hoping to reach Fiji, but wound up back at the island. Coming to the conclusion that escape from the island was impossible, Desmond again sought solace at the bottom of a bottle and drank heavily. The sailboat drifted into eye shot of the Oceanic survivor's beach camp where they discovered a heavily intoxicated Desmond inside.
Brought ashore, he told Jack that he didn't think anything else was left in the world save the island, and that they were all trapped inside a giant snow globe. As escape by boat was impossible, he let Sayid take it to scout the Others, but refused to help him sail it. Desmond told Claire not to bother injecting her baby with the vaccine from the periodic resupply drop like he did every nine days for three years, as he didn't seem to think it was real or necessary. Locke later approached Desmond, telling him he had evidence that the button was useless.
Desmond helped Locke initiate a lock down to keep Eko out of the computer room. They wanted to prevent him from pushing the button to see what happens when it's not pushed. But doubt crept into Desmond's mind and he inquired as to Locke's evidence from the second station — The Pearl. He was given a printout from the station and, scanning the dates contained on it, discovered there was a system failure on the date he failed to push the button; the same date Oceanic flight 815 crashed. Realizing that Locke was wrong, Desmond tried to enter the code, but Locke destroyed the computer. Desmond ended the manual lock down and retrieved the fail-safe key hidden inside his Charles Dickens novel. As the station began to lose structural integrity, Desmond descended into its crawlspace and activated the fail-safe device.
After activating the fail-safe device, Desmond awoke on the floor of his flat in London after falling from a ladder while painting. He was in his past, just days before he would break up with Penny, but Desmond believed his experiences on the island were nothing more than a dream or some trauma from the fall. Desmond remembered bits and pieces of his time on the island while in Charles Widmore's office and after running into Charlie outside Widmore Industries, and so talked to his physicist friend about the possibility of time travel. He attempted to use his memory of past events to prove he was experiencing events over again, but his predictions failed to prove right. Moving on with his life, Desmond attempted to buy an engagement ring for Penny, but the shopkeeper, Mrs. Hawking, told Desmond he was to have second thoughts, not buy the ring and break up with Penny. She attempted to tell Desmond that the universe has a way of course correcting and, no matter what Desmond tries to do, he's meant to end up on the island and pushing the button to save the world is the only great thing he'll ever do. Refusing to believe Mrs. Hawking, Desmond purchased the ring and met Penny, but had second thoughts and broke up with her, tossing the ring into the River Thames. Drinking his sorrows away, yet again, at a pub, Desmond witnessed his prior predictions he told his friend coming true, realizing he only got the day wrong. He believed he could fix things with Penny, but Desmond was knocked unconscious by a man at the pub.
Desmond woke up back on the island, in the jungle, stark naked. Since he had no clothes on he hid in the jungle near the beach camp. Hurley came along and gave Desmond a spare shirt. The two swapped stories and Hurley told Desmond about the bright purple light he, Jack, Sawyer and Kate saw before the Others put hoods over their heads. Desmond told him not to worry as Locke would get them back like he said in his speech, but Hurley didn't know what he was talking about as Locke never gave a speech. Desmond pretended to be confused, but Locke later made that speech and Hurley realized Desmond somehow knew of that future event.
At the beach camp, Desmond attempted to move Claire out of her shelter on the pretense of a leaky roof, but Charlie refused his offer for help. He later retrieved a 5-iron from Paulo and used it in the construction of a lightning rod near Claire's shelter. A thunderstorm quickly developed over the beach camp and the lightning rod prevented a lightning bolt from striking Claire's shelter. Later, Desmond rescued Claire from drowning, yet he was out of earshot of her yelling. Charlie pressed Desmond as to how he knew Claire was drowning and Desmond eventually told him that, after he activated the fail-safe device, he has experienced brief flashes of future events. In those flashes, he has seen Charlie die from the lightning strike and from drowning while trying to save Claire. He grimly informed Charlie that he's been trying to save his life, but it's no use as he keeps dying.
Aside from keeping Charlie alive, Desmond became more receptive in helping the survivors. Locke wanted to communicate with the Others after they captured Jack, Kate and Sawyer. Desmond believed The Swan's computer could be used to communicate with the other stations and so The Pearl's systems might be used in the same fashion. He accompanied a group to The Pearl and, after patching into a feed from The Flame, saw a mysterious man — Mikhail Bakunin — who cut the transmission. Afterwards, with Locke gone to the barracks with Kate and Sayid, Desmond became the resident hunter and successfully killed a boar.
Experiencing another flash of future events, Desmond realized someone was coming to the island. Desmond recruited the people he saw in his flash — Hurley, Charlie and Jin-Soo Kwon — and headed out along the beach. That night the group heard a helicopter overhead that crashed into the ocean, but saw an emergency beacon of a parachutist descend into the jungle. Heading towards the parachutist, Desmond discovered a pack with a copy of a photograph of himself and Penny, convincing himself the parachutist was Penny. Continuing onward, Desmond saved Charlie from being killed by one of Danielle Rousseau's traps, an event he witnessed in his flash. Desmond confided to Charlie that, by saving his life, he may have altered events and prevented himself from being reunited with Penny. He expressed doubt in continuing to save Charlie's life, believing it may be a test from God to let him die. Desmond eventually reached the parachutist, but discovered the woman wasn't Penny. The woman suffered a punctured lung from her descent and was dying. Hurley accidentally fired a flare from the woman's equipment, drawing the attention of Mikhail. He struck a deal with Desmond, save the woman's life in exchange for his release, and was successful in stabilizing her condition. However, Mikhail attempted to leave with the woman's satellite phone. Desmond retrieved the phone and let Mikhail leave.
The woman, Naomi Dorrit, eventually revealed to the survivors that the wreckage of Oceanic Flight 815 was discovered at the bottom of an ocean trench off the coast of Bali. The bodies were all there inside. She was part of a team hired by Penny Widmore to search for Desmond at a set of coordinates in the middle of the ocean. She believed it was a fool's errand as nothing was there but water, but, on her way back to her freighter, the clouds parted and she saw the island. Her helicopter's instruments malfunctioned and she crashed. Sayid attempted to fix her satellite phone, but discovered it was being jammed by Rousseau's distress signal.
The survivors eventually learn from Jack and Juliet that the Others were planning a raid on the beach camp to abduct any pregnant women. A plan was formulated to ambush the Others while Jack led the remaining survivors to the island's radio transmitter to deactivate Rousseau's distress signal so they can contact Naomi's freighter. A wrench is thrown into the plan when Juliet revealed the existence of The Looking Glass, an underwater DHARMA station being used by Benjamin Linus to jam all communications off the island. Desmond revealed to Charlie another one of his flashes, this one of Claire being rescued by a helicopter due to Charlie flipping a switch in the station and drowning. Wanting to get Claire and her child off the island, Charlie volunteered to go to The Looking Glass and Desmond volunteered to go with him.
Traveling to the station by outrigger canoe, Charlie prepared to dive down to it. Desmond decided to stop Charlie from going down and subsequently dying, believing perhaps he was meant to die in his place. Charlie would have none of it, however, and knocked Desmond unconscious to prevent Desmond from stopping him. Desmond awoke to find Charlie gone, but Mikhail was at the shore firing at him. To escape, Desmond dove down to The Looking Glass, found Charlie captured and hid. Mikhail, on Ben's orders, turned on the two Others occupying the station, killing one and fatally wounding the other. Desmond prevented Mikhail from finishing off the second Other by firing a spear gun into his chest. The Other, Bonnie, revealed the deactivation code to Charlie before she passed away. While Desmond retrieved scuba equipment, Charlie deactivated the jamming equipment and received a transmission from Penny. Desmond noticed Mikhail's body had disappeared and, before he could warn Charlie, Mikhail detonated a grenade outside the window to the room Charlie was inside. In order to prevent the entire station from flooding, Charlie secured the door to the room, sealing his fate. Before he drowned, Charlie wrote a note to Desmond on his hand: "NOT PENNY'S BOAT".
Desmond returned to the beach camp with news of Charlie's death and warning. Sayid believed the freighter was monitoring their communications, so they set out for the radio tower to warn Jack in person. They made it to nose section wreckage of Oceanic 815 where they were met by the other survivors. There everyone learned of Charlie's warning and the survivors split into two groups: those that believed Charlie went with Locke to the barracks while those who believed in rescue stayed with Jack. Desmond took his chances with Jack and returned with the other survivors to the beach camp. Juliet took him from the camp to where the freighter's helicopter had landed. He confronted the pilot, Frank Lapidus, with the picture Naomi had of himself and Penny. He wanted to know if the truth, but neither Frank or Daniel Faraday were forthcoming. Determined to discover the truth, Desmond left the island in the helicopter with Sayid.
During the ride to the freighter, the helicopter was forced to fly through a thunderstorm in order for Frank to follow Daniel's specific bearings. But the turbulence forced the helicopter slightly off course and Desmond's consciousness from 1996 inhabited the present-day Desmond. The helicopter made it to the freighter, but Desmond was bewildered and didn't know what was going on. He was escorted to the freighter's sick bay and met George Minkowski, the freighter's communications officer, who was also experiencing the same effects when he and another crew member took a tender out to catch a glimpse off the island. The crew member died and Minkowski was forcibly restrained while his consciousness traveled back and forth in time. With Sayid and Frank's help, Desmond was put into contact with Daniel and told to travel to Oxford to find him there when Desmond traveled back to 1996. He received instructions from the 1996 Daniel in how to stop the effect before it killed him. He had to find his constant: he had to talk to Penny in both 1996 and 2004. Desmond eventually got Penny's new phone number in 1996 and told her to be there on December 24, 2004 as he would call her. In 2004, Desmond and Sayid made it to the freighter's communications room and Sayid jury-rigged the smashed equipment so Desmond could call the mainland. He finally spoke to Penny after three long years on the island, and Penny said she knew about the island and promised to find him. Before the battery died, the two told each other they loved one another.
- Information is shown in chronological order. Episodes in bold are flashback episodes.
Before the Shipwreck
- 3x17 - Catch-22: Becomes a monk at a monastery, but is later fired from the job. Meets Penelope Widmore.
- 3x08 - Flashes Before Your Eyes: Asks Charles Widmore for his permission to marry his daughter, but is turned down. Breaks up with Penny.
- 2x24 - Live Together, Die Alone: Desmond is released from military prison, discovers that Charles Widmore has kept the letters he wrote to Penny and never gave them to her. Desmond vows to get his honor back.
On the Island
- 2x24 - Live Together, Die Alone: Desmond shipwrecks on the island and is taken to the Swan bunker by the mysterious Kelvin. Desmond misses pressing the button, and inadvertently causes the crash of Oceanic flight 815.
- 2x01 - Man of Science, Man of Faith: After descending down the shaft covered by the hatch, Kate, Locke and Jack meet Desmond.
- 2x03 - Orientation: After trying to fix the computer terminal he uses to stop the countdown in the bunker, Desmond gives up and resolves to get as far from the bunker as possible. We last see him walking off into the forest after telling Jack the numbers he needs to stop the countdown.
- 2x24 - Live Together, Die Alone: Desmond returns to the island in the sailboat he crashed in on accident, he claims that they're trapped in a "snow globe." He activates the Swan's fail-safe device and travels back in time.
- 3x03 - Further Instructions: Desmond seems to exhibit pre-cognition of a speech Locke is going to make.
- 3x08 - Flashes Before Your Eyes: Reveals to Charlie that he experiences flashes of future events.
- 3x17 - Catch-22: Has a flash of a person coming to the island and believes that it is Penny. Desmond finds her, but she is not Penny. Desmond once again saves Charlie's life.
- 3x21 - Greatest Hits: Reveals to Charlie that Charlie must die in order for Claire to be rescued.
- 3x22 - Through the Looking Glass: Accompanies Charlie to The Looking Glass and learns that Naomi's freighter does not belong to Penny.
- 4x01 - The Beginning of the End: Arrives back at the beach and informs everyone that Naomi's people are not who they say they are. When the group split in two, Desmond stays with Jack's group, still hoping to get rescued by the freighter.
- 4x05 - The Constant: Becomes unstuck in time and arrives on the freighter; talks to Penny.
- 2x24 - Live Together, Die Alone: Desmond remembers Penny and says that he loves her before he turns the failsafe key.
- 3x03 - Further Instructions: Desmond seems to predict the future.
Famous Names: Desmond's full name is Desmond David Hume. David Hume was an 18th century Scottish philosopher of the Enlightenment. He was influenced by John Locke's works, but was also a critic of some of his theories.
Parallels to "The Odyssey": Desmond's journey obviously parallels The Odyssey to a large degree. Odysseus sets off for Troy to satisfy his honor, but cannot return home and is waylaid by Poseidon, god of the seas. However, there are more than just superficial similarities:
- Book II - Odysseus's wife, Penelope, has to fight off suitors while waiting 20 years for her love to return. Penelope Widmore is the name of Desmond's love, and she seems to be waiting for Desmond, if not actively searching for him. She was planning be married to someone else before Desmond set sail, but still isn't married three years later. It should also be noted that Penelope is said to have 108 suitors, the same number to which the countdown in the hatch re-set itself to.
- Book IX - Trapped on an island by a cyclops (a one-eyed man). More of a stretch, especially since there's no proof that Dr. Marvin Candle has a glass eye at all.
- Book X - Odysseus sets out but is pushed back to where he left when he opens a leather bag containing the wind. Mirrors exactly what happened to Desmond between the start and end of this season.
- Book XII - Odysseus lands on the island of Helios, the sun god. Note that The Colossus of Rhodes was a statue of Helios, and the statue foot they see looks very much like you'd expect the Colossus of Rhodes' foot to look like.
- Book I and XII - Odysseus spends many years trapped on an island with Calypso, who refuses to allow him to leave. This vaguely parallels Kelvin/Desmond's relationship in the Swan bunker.
- 2x02 - Adrift: "What did one snowman say to the other snowman?"
- 2x03 - Orientation: "It was three years ago. I was on a solo race around the world. My boat crashed into the reef and then Kelvin came. [...] Kelvin. He comes running out of the jungle. 'Hurry, hurry, come with me!' He brings me down here. First thing he does, 'cause it's beeping already, he types in the code, he pushes the button and it stops. 'What was all that about" I say? 'Just saving the world' he says. [...] His words, not mine. So I started pushing the button, too. And we saved the world together for a while and that was lovely. Then Kelvin died and now here I am all alone. The end."
- 2x03 - Orientation: "Every. Single. Day."
- 2x03 - Orientation: "See you in another life, yeah?"
- 2x23 - Live Together, Die Alone: "Three days before you came down here, before we met, I heard a banging on the hatch door — shouting. But it was you, John, wasn't it? You say there isn't any purpose, there's no such thing as fate. But you saved my life, brother, so that I could save yours."
- 2x23 - Live Together, Die Alone: "See you in another life, brother."
- 3x03 - Further Instructions: "Don't worry. Locke's gonna go after [Jack, Kate and Sawyer]. He said so in his speech."