Justin Hammer is a supervillain from Marvel Comics. A millionaire and rival business owner of Tony Stark, Hammer is the CEO of Hammer Industries, intent on developing technology far more advanced than the Iron Man armor or anything Tony builds in order to overtake his place as a captain of industry, however, has resorted to underhanded to outright villainous methods to obtain this goal, such as enlisting or collaborating with supervillains. He is the secondary antagonist of the 2010 film Iron Man 2, enlisting Ivan Vanko's help in creating the Hammerdrone line.
Iron Man 2
Hammer is first seen when Senator Stern called him to declare that the technology created by Tony is a risk to the United States. Hammer tries to discredit Stark showing US enemies trying to create their own armor but eventually is humiliated by Tony who shows a video to the public showing that Hammer also does the same thing.
Hammer meets again with Tony in Monaco, he is accompanied by the reporter Christine Everhart. When Tony tells her that Hammer lost the contract with the government she leaves him. Later, he is shown interested in the technology used by Vanko to attack Tony, then he sends him release from jail for help to discredit Tony. When he learns that Vanko doesn't comply as promised, Hammer gets mad and takes the pet of Vanko.
After James Rhodes steal one of the Tony's armor, Hammer is called in to improve it. Hammer weaponizes the armor with the best weapons of Hammer Industries. In Stark Expo, his presentation is interrupted by Iron Man, who knows that Hammer is working with Vanko. At that moment, Vanko takes control of the Drones to make these attacks against Tony and the public. Hammer with his technicians tries to take control of Drones but is stopped by Pepper and Natasha Romanoff, who obliged him to give the whereabouts of Vanko. Hammer is arrested after it was discovered that he freed Vanko from jail.
In All Hail the King, Hammer is sitting beside a fellow prisoner and boyfriend, wondering what is so special about Slattery. Hammer says Slattery had no army of robots and also has a silly accent. At that time he is seen reading a Forbes Magazine with Pepper Potts on the cover.
Marvel Animated Universe
He also appeared in Avengers Assemble as a wannabe super villain. He created the robot Adaptoid Android to take on the Avengers. He also mined Vibranium in the Savage Lands and acquired an army of Raptors to fight the Avengers.