Jack Harkness is an intergalactic con-man from the 51st century, probably the United States or its future equivalent. Originally a time agent, he woke up one morning to realize that the agency had removed two years of his memory. Wanting to recover them, he renounced his title of captain and quit the agency to go freelance, although he ended up putting his skills to use in less-than-legitimate ways. In pursuit of his latest scam, Jack - having seen the TARDIS in flight, and believing the Doctor and Rose to be time agents - threw an empty Chula ambulance toward Earth past the TARDIS, so that the Doctor would track it there, believing it to be valuable. Jack then planned to park it at a future bomb impact site, sell the ambulance to the time agents under the pretense of it being a fully-equipped Chula warship, and collect half the money before the bomb hit, destroying the ambulance before the time agents could learn that it was junk. To pass the time, he posed as an American volunteer in the 133 Squadron of the Royal Air Force in 1941 London. When his plan backfired, Jack was forced to stop the bomb from impacting at the site, and transported it to his ship so that he could carry it away from Earth. However, he was then unable to either transport the bomb or himself off his ship before it exploded. Resigned to dying, he was surprised to find that the Doctor and Rose, grateful for his help, had materialized the TARDIS onboard his ship to rescue him.
Jack has a very outgoing personality. He is likeable, friendly, possesses a good sense of humor... and he is a huge flirt. Being bisexual, as is apparently the norm among humans of the future, he is equally likely to work his charm on men and women. His adventurous spirit apparently extends to the bedroom - he has, at the very least, slept with two of his would-be executioners (a male/female couple?) and a British soldier named Algy (male). He is also quite the party animal; Jack enjoys dancing, and he especially enjoys drinking - champagne, martinis and hyper-vodka being among his libations of choice. He is a great raconteur, easily keeping people entertained with his outlandish and amusing stories.
Jack's fun-loving side feeds directly into his great love of adventure. The more daring and perilous the escapade, the better the story he will be able to tell. His outgoing, bold nature also makes him a natural leader. He has charisma, he commands attention, and he also happens to be an excellent strategist. He is also no shirk in a fight; he is quite good at hand-to-hand combat, and is adept with weaponry, particularly guns, which he can even adapt to suit his purposes. Along with his weapons prowess, Jack is talented at tinkering with machinery, even being skilled enough to make repairs and modifications to the TARDIS systems.
Despite his combat-related skills, he claims to have been a coward when he first met the Doctor, probably because he preferred to make an easy buck and escape before things could go wrong. However, once he discovers a cause worth fighting for, he accesses reserves of bravery he never realized he had. The Doctor, in particular, inspires him to fight for good; so much so, in fact, that Jack trusts the Doctor completely. He even states that he "never doubted" the Doctor.
Jack wears a device on his wrist that mainly functions as a scanner (both for alien technology, and for medical purposes) but can also project holographic displays and home in on the TARDIS. He also carries a sonic blaster, which can serve as a sonic cannon or disruptor, from the weapons factories on Villengard. It is battery-powered, with a digital blast pattern and digital rewind (which enables him to instantly undo any damage caused by the blaster).
For a while, Jack was in possession of a Chula ship that he stole from a "gorgeous" woman. The ship was outfitted with a variety of modern conveniences, including a light-field tractor beam, a medical scanner and nanogenes, an emergency teleport security-keyed to his molecular structure, a food synthesizer, a signal jammer, invisibility technology, om-com technology (which enables him to call anything with a speaker grille), a voice-activated interactional computer, a pair of very soft beds, but no escape pods. However, the ship was presumably destroyed when the German bomb exploded inside it.
Jack is tall, with dark brown hair, blue eyes, a wide smile, a cleft chin, and a toned body (he works out) of which he is very proud. He knows how to speak at least a little Spanish, although his Iberian accent implies that he has acquired some level of proficiency. He seems to be quite fond of clothes, and showing off in (or out of) them.
During the battle with the Daleks on the Game Station, Jack is killed by the Daleks while trying to buy time for the Doctor to complete his delta wave transmitter. Shortly thereafter, he is brought back to life by Rose, harnessing the power of the time vortex. However, like Tegan before him, he is (inadvertently?) abandoned by the Doctor and Rose when they leave without him in the TARDIS.
