Jack Staff is Britain's Greatest Hero, has been active since at least WWII. While he has revealed he has been around since the Victorian Age , its unknown if he was active as a superhero or similar adventurer. In his civilian identity, he works as a builder by the name of John Smith, it is unknown if this is his real name.
It has been mentioned by other characters that Jack's record of success is a bit iffy; he often gets beaten up by supervillains and ends up in embarrassing or dangerous situations, such as being set-up to be arrested by the Spider.
Agile and acrobatic, the only clearly defined power of Jack Staff is his ability to move energy. This has been shown by his moving energy into his staff to break through solid walls, or move the anger from Hurricane. This ability is never clearly defined with regard to where the energy is moved from, or what kind of energy is involved.
Jack appears to be either immortal or very long lived. He reveals that he has been around since the at least the Victorian era. He was active as Jack Staff during World War II up until the 1980s when he retired after the Hurricane incident. He looks no different today then he did during World War II. No further background on him has yet to be revealed, although there have been hints of a connection with the "Eternal Warrior".
He has had dreams of some future threat, Becky Burdock is also plagued by the same thing, though it affects her more frequently.