This version of King is immortal, but this is triggered only when he gets killed. It allows him to be reckless and unpredictable.
The King has long been a member of various incarnations of the Royal Flush Gang, a group of villians with a playing card motif. A previous version of King had charisma/hypnosis based abilities. Prior to that the Royal Flush Gang just relied on gadgets. They have pestered the Justice League for years, but have never really been a big threat.
King has been in a few episodes of Batman Beyond.
King will be appearing in the Arrow TV Series and he will be played by Currie Graham.