Someone in life or in art who does the right (good, moral or noble) thing but for WRONG (short-sighted, self centred or just plain selfish) reasons.
Anti-Hero-Clint Eastwood in almost all of his Western's.
Anti Heroes- Beavis and Butthead in the episode where they save a man who has crashed in a light plane. They try to flag down a car so they can go and get a camcorder to film the wreck and sell it to television.
In the process they inadvertently alert the emergency services who save the man.
Subsequently they appear on "Rescue 911" where they are portrayed as bonafide heroes.