Torchwood's team leader. Jack's origins are obscure and he likes it that way. However, he has vast practical experience of working with aliens and dealing with crisis situations. He has come through a lot of scrapes intact, and is unafraid of dangerous situations. In fact, he's usually ready with a flirtatious quip whatever the threat.

In Torchwood: Children Of Earth, Jack’s already tense relationship with the Government brings him right into the line of fire as he becomes a target for the mysterious assassin Johnson and her soldiers.