
Justin Hammer first appeared in Iron Man #120 (March 1979), and was created by David Michelinie, John Romita Jr., and Bob Layton. Sam Rockwell portrayed the character in the Marvel Cinematic Universe film Iron Man 2 (2010), and the short film All Hail the King.

Hammer reveals that the villains are his underworld mercenaries, secretly armed and contractually obliged to fulfill missions against Hammer's competitors and enemies, such as Tony Stark. As he explains in his first major appearance, he is the reason why many of Iron Man's supervillain enemies have access to extremely advanced technology and why these foes use their equipment for violent crimes instead of profiting by bringing the designs to market. The character is depicted as a villainous entrepreneur and a frequent adversary of the superhero Iron Man.

Justin Hammer is a fictional character appearing in American comic books published by Marvel Comics.
