While most hitmen try to keep it low key, that just wasn't Campbell's style. He was a ladies man who liked expensive cars, good clothes, and fine liquor. Unusually, he was a favored contract killer among both urban street gangs and Mafia types, and he was known for especially sophisticated crimes. His surveillance equipment and planning would have rivaled anything used by the CIA at the time, and he seemed to enjoy stalking his targets before killing them. That almost puts Campbell more in the vein of a serial killer, albeit one who killed professionally. Campbell also enjoyed collecting guns and weapons, and was said to have had an arsenal containing everything from silenced .22 pistols to machine guns to rocket launchers.
Campbell operated with near-impunity among police owing to the vast quantities of damning blackmail material he collected on key figures in the department. In fact, a big part of what made Campbell so dangerous was his capacity for collecting huge amounts of information on seemingly anyone. Suave, stylish, smart, and deadly, Campbell was part James Bond, Part John Shaft, and part brutal mercenary killer, with a bit of comic book supervillain sprinkled in as well.