H is for... Harkness, Captain Jack

An ex-Time Agent from the 51st Century who became companion to the Ninth Doctor, before leading Torchwood 3 based in Cardiff. Jack was born in a colony on the Boeshane Peninsula. The settlement frequently came under attack by alien creatures, and during one of these assaults his younger brother Gray was taken. As he had been looking after him, Jack felt responsible for this loss. He later joined the Time Agency as one of its operatives, forging a personal and working relationship with fellow agent Captain John Hart. Following one of their missions, the Agency deleted two years of Jack's memories, which caused him to resign.
He set himself up as a con-man, and one of his schemes involved the sale of a Chula Warship - to be sold under cover of the London Blitz. Jack took on the persona of a dead US RAF volunteer. His real name has never been revealed. The warship was really a Chula ambulance, containing millions of nanogenes designed to repair injured Chula warriors. They escaped into the atmosphere and began rewriting the DNA of anyone they encountered. When Jack rescued the Doctor's companion Rose Tyler, he assumed from her anachronistic clothing that she and the Doctor were the intended buyers.
Jack was prepared to sacrifice himself to carry a German bomb into space, before it could destroy the alien ambulance. He was rescued by the Doctor and Rose and accompanied them on their travels, visiting present day Cardiff and medieval Japan, before the TARDIS and its crew were captured by the Daleks and placed on the Game Station, around the year 100,100 AD.

Jack found himself in a deadly version of the TV fashion show What Not To Wear, menaced by its robot presenters. Despite being naked, he somehow smuggled a compact laser about his person and was able to destroy them. He then joined the Doctor in attempting to defend the station from a Dalek assault. He was able to work out that the game show contestants were not being vapourised, but were really being teleported away to the Dalek fleet for conversion into Daleks. His efforts to halt the Daleks ultimately failed as the overran the station, and Jack was exterminated.
However, Rose had absorbed the Vortex from the heart of the TARDIS, and she used her powers to bring him back to life. The Doctor saved Rose but at the cost of his own life, and so he rushed away from the station with her before he regenerated - leaving Jack behind. As a Time Agent, he possessed a wrist-mounted device known as a Vortex Manipulator, which allowed him to travel in time. He used it to travel to present day Earth where he hoped to find the Doctor and Rose. However, the device left him in the Victorian era where it malfunctioned - leaving him stranded. He then discovered during a drunken brawl on Ellis Island, New York, that every time he was fatally wounded he healed, or if killed came back to life. Rose had not only brought him back to life, she had made him immortal.
He decided that he would have to live out his life on Earth until his path crossed once again with the Doctor, who might be able to help him.
Back in England, he soon came to the attention of the recently formed Torchwood organisation, who were set up to protect Britain from alien menaces - including the Doctor. Rather than be locked away, he was forced to work for them.

He was based in Torchwood's Cardiff Hub, built beneath the city's bay area, but went on missions all over the country. In the 1960's he was in Scotland, where he was tasked with handing over a number of children from an orphanage to aliens known as the 456. On the eve of the Millennium, his boss killed his entire team before taking his own life - bequeathing Torchwood 3 to Jack before he died. He had claimed that everything was going to change for the worse with the coming of the 21st Century, and believed that they were doomed. Jack then set about building a new team. In 2006 he came into the possession of the Doctor's severed hand - cut off in a duel with the Sycorax leader over London on Christmas Day. Jack kept this, as he felt it might lead to another meeting with the Doctor. When he recruited WPC Gwen Cooper to the team, it coincided with his having to kill his deputy Suzie Costello, who had become obsessed with an alien gauntlet which could revive the dead - prompting her to commit murders so that she could use it. Investigating an abandoned music hall, Jack and colleague Toshiko Sato were transported back to the Cardiff Blitz, where he met the man whose identity he had taken - the real Captain Jack Harkness.
Soon after Jack was almost killed when he faced the demonic Abaddon. On recovering from the ordeal, he noticed that the Doctor's hand was reacting, and he spotted that the TARDIS had arrived above the Hub to refuel from the space / time rift which ran through the city. He leapt onto the ship as it dematerialised, and his presence caused the TARDIS to fly to the end of the universe.

He was at last reunited with the Doctor, now in his tenth incarnation and travelling with Martha Jones. The TARDIS had recognised him as a temporal anomaly and had tried to avoid him - hence the trip to the end of time and the planet Malcassairo, home to one of the last remnants of the human race. The Doctor admitted that he could not help Jack. Jack helped the humans take off in their spaceship in search of a place called Utopia, where other survivors may have gathered. The elderly Professor Yana had declined to accompany them. He proved to be the Master, his identity hidden from himself by a Chameleon Arch. Earlier, the Doctor had been told by the Face of Boe "You Are Not Alone" - implying that he was not the last of the Time Lords as he had believed. The Master stole the TARDIS and used it to get to Earth, and the Doctor repaired Jack's Vortex Manipulator so that they could follow him. They arrived some months later - to find that the Master, as Harold Saxon, had just been elected British Prime Minister. he then arranged for the planet to be invaded by the Toclafane - cyborg remnants of the human race from Utopia. Jack was left chained up for a year in the Valiant, the Master's base of operations which had been a UNIT flying aircraft carrier.
The Master was eventually defeated and time rolled backwards to delete the year of his misrule for everyone except those on the vessel. jack was dropped off back in Cardiff, where he told the Doctor and Martha that he had once been nicknamed the Face of Boe, when he became the first person in the Boe Peninsula to join the Time Agency...

Jack rejoined his team, who were not happy that he had seemingly abandoned them. He resumed his relationship with team member Ianto Jones. He was reunited with Captain John and from him learned that his brother Gray was still alive. Later, he encountered an alien who called himself dam, who thrived on people's memories - needing to be remembered in order to exist. Adam tried to infiltrate the team by planting false memories, to make everyone think had always been with them. He was able to access Jack's memories of the day when Gray had been taken - memories which he tried to suppress. Jack was prepared to lose these again to destroy Adam, giving himself and the rest of the team the Ret-con drug, which caused memory loss.
Some time later, however, the team was lured into an ambush - a trap set by Captain John and Gray. Gray had become deranged following years of captivity and wanted revenge on his brother. He set off bombs around Cardiff, then abducted Jack and took him back to the city in the Iron Age, where John was forced to bury him alive. Jack remained imprisoned this way, dying over and over again, until a device planted in the grave by John attracted the attention of the Edwardian Torchwood team. Jack had them place him in cryogenic suspension in the Hub, to be reawakened on the day Gray attacked the city. Jack was able to overpower Gray and had him placed in cryogenic suspension, but the incident had already led to the deaths of Tosh and colleague Owen Harper.

Jack, Ianto and Gwen had no sooner got over the loss of their colleagues when the entire Earth was dragged across space to the Medusa Cascade, before being invaded by Daleks. Jack was reunited with Martha Jones, now with UNIT and who had been temporarily seconded to Torchwood. He also got to meet Sarah Jane Smith, whose exploits he had followed closely. He had left Ianto and Gwen to defend the Hub and gone off alone to help the Doctor. Jack allowed himself to be exterminated once again by the Daleks in order to remain at large on their space station - the Crucible. Here he would also be reunited with Rose, and Mickey Smith. Everyone was captured by Davros and the Daleks, but they were rescued by Donna Noble and a second Doctor who had grown from the severed hand which Jack had once kept, following a partial regeneration.
Jack returned to Cardiff after the Daleks had been defeated and the Earth restored to ts rightful location.
Whilst investigating mysterious deaths at the city's hospital, Jack was knocked out and awoke to discover that a powerful bomb had been sewn into his body. Gwen and Ianto managed to escape before it detonated, but Jack was blown to pieces and the Hub destroyed. The 456 had returned, and the British government was eliminating everyone associated with their earlier visit. Jack was rescued after he had come back to life, despite the government assassins encasing his remains in concrete. He, Gwen and Ianto went on the run, travelling to London. When they managed to get into the building where the 456 had materialised. Jack and Ianto were poisoned by toxic gases released by the creature. Jack returned to life, but Ianto perished.

Jack had had a number of relationships over the years. One of these had been with a lady named Estelle, where he later pretended to be the son of the man she once loved. Another relationship had led to a daughter, Alice Carter, and a grandson, Steven. A means of ejecting the 456 back out into space was discovered, a conflicting frequency, but it would require a child to deliver it - something which would prove fatal. Jack decided to use his own grandson to act as the conduit for the frequency. The 456 were expelled, but Steven was killed. Guilty and bereaved, jack decided to leave Earth for time - unsure if he would ever return.
The Tenth Doctor came across him in an alien bar as he visited old friends and companions prior to his next regeneration. He set Jack up on a date with Midshipman Alonso Frame, late of the Starship Titanic, who was also in the bar and feeling sorry for himself.

Jack returned to Earth, where he ensured that Gwen and her husband Rhys, with their baby daughter, were safely hidden in a remote farmhouse. Then one day, no-one on Earth died. Jack discovered that he was now the only person on the planet who could die. Gwen was forced out of retirement to accompany Jack to the USA to investigate what became known as Miracle Day. It transpired that it was created by an international conspiracy, centred on a group known as the Three Families. As Jack investigated, he discovered that he was the cause of the phenomena. On an earlier visit to the USA in 1927 he had become the lover of a young Italian immigrant named Angelo Colesanto. The two worked together and one night Angelo had seen Jack killed, before he was arrested and sent to prison for a year. On his return, he was shocked to find jack still alive, and believed him to be a devil. He stabbed him - and discovered that he could not die. He and some others - who would become the Three Families - took some of Jack's blood, and they had later used this to bring about Miracle Day - by feeding it into a strange rock formation which ran through the Earth. Known as the Blessing, this maintained a morphic field which stopped people dying. Feeding Jack's blood into both ends of the field, across the globe from each other, negated it - and mortality resumed.

Update:
Missing for nearly 10 years, Jack suddenly reappeared far from Torchwood in 2020, when he unsuccessfully employed a teleport to scoop up the Thirteenth Doctor from Earth. A forcefield erected around the city of Gloucester by the Judoon caused him to transport Graham O'Brien instead, and later his grandson Ryan and their companion Yaz, who were travelling with the Doctor at the time. They were on a stolen spaceship which was coming under enemy fire. Jack only had time to ask the Doctor's companions to warn her about a "Lone Cyberman", which threatened to resurrect a dead empire should the Doctor do as it wanted. Jack was then attacked by the ship's defensive nanogenes, but stated that he would reappear when the Doctor needed him...

Played by: John Barrowman, Jack Montgomery (young Jack). First appearance: The Empty Child / The Doctor Dances (2005). Last appearance: Fugitive of the Judoon (2020).