He is a hitman, mercenary, and assassin that often supports with the top crime bosses of the criminal underworld. Not only is he an extraordinary marksman, but in his hands, anything is a weapon, and he almost never misses, hence his supervillain codename.
Kingpin had him incriminate Daredevil, and for a considerable amount of time Bullseye acts as both Kingpin's main enforcer and Kingpin's inside man on the FBI. In the end, Daredevil managed to defeat Bullseye.
Bullseye was created by Marv Wolfman and Bob Brown.