Killer Joe Cooper is a fictional character from the play and film titled "Killer Joe." Created by playwright Tracy Letts, he is a hitman hired by a dysfunctional family to eliminate a member for insurance money. Joe is portrayed as both charming and menacing, embodying the complexities of morality and desperation. In the story, Joe's presence escalates the family's already tense dynamics, leading to dark and unexpected consequences. The character is known for his cold demeanor and ruthless efficiency, making him a memorable figure in contemporary American theater and film.