Despite featuring some of the best recurring adversaries to the Doctor, like the Master, the Doctor Who series also isn’t short of its good guys, including the dashing and the brave Captain Jack Harkness.

But who exactly is Captain Jack Harkness, what’s his relationship with the Doctor, and how has the character evolved through one of television’s longest-running series?

Who Is Captain Jack Harkness?

“Captain Jack Harkness” is a pseudonym adopted by a former Time Agent turned conman Javic Piotr Thane, who appears in the Doctor Who and Torchwood television series, where he’s portrayed by John Barrowman, and The Lives of Captain Jack Harkness audio series, where he’s voiced by the same actor.

He’s introduced to the Who universe in the New Who era, during Christopher Eccleston’s tenure as the Ninth Doctor, though chronologically, he first met Colin Baker’s Sixth Doctor in the aforementioned audio series.

Captain Jack Harkness is a known associate of the Doctor, mainly cooperating with Christopher Eccleston’s Ninth Doctor, David Tennant’s Tenth Doctor, and had a brief encounter with Jodie Whittaker’s Thirteenth Doctor in 2021’s festive special episode Revolution of the Daleks.

Though seemingly mundane, John Barrowman’s Captain Jack Harkness is actually a time-traveling human from the 51st century, originating from the Boeshane Peninsula — one of Earth’s future colony worlds. He later signs up for the Time Agency, an organization tasked with the safekeeping of time, and garnered the nickname the “Face of Boe”. Did we mention he’s also immortal?

The Abilities of Captain Jack Harkness

As a time-traveling agent, conman, and later companion, Jack Harkness possesses several unique abilities. 

Evolved Pheromones

As a human from the 51st century, Captain Jack Harkness has an evolutionary “advantage” over typical humans/companions found in the Doctor Who series. This advantage comes in the form of evolved human pheromones, which made him naturally nice-smelling and attractive to others.

In fact, in the episode The Doctor Dance, Jack recalls being sentenced to death. Thanks to his evolved human pheromones, he managed to seduce and bed both executioners at the same time, referring to them as a lovely couple that has stayed in touch. Of course, there was some hypervodka involved as well.


One of his most crucial abilities is his immortality and the range of other abilities implied by the detachment of death, like resistance to heat and radiation. However, his immortality isn’t innate to his being; it was accidentally acquired through a failed resurrection process.

Jack was brought back to life by Rose Tyler as the Bad Wolf after he was killed by the Daleks on Satellite 5. However, Rose couldn’t control the newfound powers she wielded at the time, and instead of simply resurrecting Jack, Rose brought him back forever.

Because of this, Jack became a fixed point in time and space, and as a result, he is now eternal, never aging past his prime, and never capable of truly dying. Whenever he did die, he would resurrect almost instantly, followed by a deep breath as his respiratory system became active again.

Severe trauma could delay his resurrection; he once recovered from being blown up by a bomb, regenerating himself from just his arm. His body would first grow the bones, followed by internal organs, flesh, and skin. This also meant that he could regain consciousness during still incomplete resurrections and feel all the pain associated with the current state of his body.

Resistance to Heat and Radiation

The advantages, besides immortality, were resistance to heat and radiation, which had no effect on him due to his regenerative capabilities, which would keep him in nearly perfect health at all times. Smaller injuries, like superficial cuts and bruises, will remain and heal at the rate of a normal human.

Non-extraordinary Abilities

Other than the evolved pheromones and immortality, Jack had no other superhuman abilities. However, he was physically strong and fit, a skilled fighter with extremely fast reflexes, and an expert in firearms.

Key Appearances of Captain Jack Harkness in Doctor Who

So far, Captain Jack Harkness has appeared nine times in the entire Doctor Who series, not counting for the Torchwood spin-off. Here’s a list of his appearances.

  • The Empty Child/The Doctor Dances (Series 1, New Who)
  • Boom Town (Series 1, New Who)
  • Bad Wolf/The Parting of the Ways (Series 1, New Who)
  • Utopia (Series 3, New Who)
  • The Sound of Drums/Last of the Time Lords (Series 3, New Who)
  • The Stolen Earth/Journey’s End (Series 4, New Who)
  • The End of Time (Series 4, New Who)
  • Fugitive of the Judoon (Series 12, New Who)
  • Revolution of the Daleks (Series 12, New Who)

The Doctor and Jack Harkness Connection

While there are previous records of Jack traveling with the Doctor before the time he met Rose, the most common account of Jack and Doctor’s first encounter states that the two met during the London Blitz in The Empty Child episode.

He became a recurring member of Team TARDIS throughout the Season One of the new Who series, up until he became immortal and was unfortunately stranded in the year 200,100. He was left there purposefully by the Doctor, explaining that Jack’s nature fixed in time and space now prevented normal functioning of the TARDIS.

However, despite being on friendly terms, the Doctor and Jack have very little in common in terms of their respective physiologies. Jack resurrects himself as a response to fatal injury and does have some instantaneously regenerative abilities, but those aren’t similar to the Doctor’s ability to regenerate in any way.

While the Doctor’s regeneration is a part of his Time Lord physiology, allowing him to regenerate entirely from old age or fatal injuries, Jack’s resurrection is entirely different. Sure, it allows him to regenerate as well, but unlike the Doctor, Jack apparently can’t be permanently killed. By all accounts of the Doctor Who series, Captain Jack Harkness is endless.

How Jack Harkness Became Immortal

As we previously said, he was resurrected by Rose Tyler, who had become the Bad Wolf after absorbing Time Vortex energies, during the Dalek invasion of Earth in the 2002nd century. However, Rose didn’t have full control of her powers and ended up resurrecting Harkness forever — a gift he sometimes saw as a curse.

How Captain Jack Harkness Has Changed Over Time

Apart from becoming immortal in the series, Jack Harkness remained a forever dashing and handsome character that didn’t see much development over the course of the Doctor Who series.

Most of his character’s backstory and numerous adventures were explored in the Doctor Who spin-off series, Torchwood, which ran for four seasons, before concluding its run in 2011.

What More Can We Speculate about Captain Jack Harkness in the Future

According to numerous reports, the future of Captain Jack Harkness within the Who universe is questionable, at best. John Barrowman has been systematically distanced from the projects tangentially connected to the Doctor Who series following the stings of accusations questioning his on-set professionalism and discipline.

Captain Jack Quiz


Doctor Who Has Long Hinted That Jack Harkness Will Evolve Into the Oldest Living Creature in Existence One Day with What Apt Name?

Correct! Wrong!

In Doctor Who Spin-Off "Torchwood," What Was Revealed to be the Name of Jack's Long Lost and Thought Dead Brother?

Correct! Wrong!

How Did Jack Know That if He Based Himself in Cardiff the Doctor Would Eventually Make an Appearance?

Correct! Wrong!

After the events of Jack's Resurrection on Satellite 5 What Year did the Vortex Manipulator End up Stranding Him on Earth?

Correct! Wrong!

In Torchwood: Children of Earth What Was the Unusual Reason the 456 Wanted Human Children?

Correct! Wrong!

Captain Jack Harkness Quiz
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Jason Collins

Contributing Writer, BuddyTV

Jason Collins is a freelance Pop Culture Journalist with a degree in English Literature. While he has had the distinct privilege of seeing Tom Baker up close he was not offered any Jelly Babies which was highly disappointing. When he’s not out on the hunt for the latest and greatest podcast he is lounging at home with more cats than he would care to disclose at this temporal moment.