Justin Hammer is a business rival of Tony Stark. Hammer represented one of the many factions who attempted to replicate the Iron Man armor but failed in all areas. The test pilot in the Hammer suit barely survived being twisted one-eighty degrees around. The footage of this incident was shown publicly by Tony Stark during his hearing with Senator Stern, to prove that there was no need for him to hand over the Iron Man armor to the U.S. government. Justin Hammer meets Stark again in Monaco, where both of them are supporting one of the cars involved in the race. When Whiplash attacks Stark during the race, Hammer is greatly impressed by his armor and whips. When the villain is arrested, Hammer has him freed by prison and taken to a secret storage, in which the two of them forge an alliance. He wanted Vanko to improve on his developing suits so that he could upstage Stark at the upcoming Stark Expo. Vanko agreed to do so, if Hammer brought him his parrot he left back in Russia; Hammer seemed to have brought the parrot to him, but Vanko claimed that the parrot wasn't his. Justin soon discovered that Vanko modified the armors to be remote-controlled drones, unaware of the plans that were to follow afterwards.
When Hammer learned that Stark was in disgrace after a drunken binge at his own birthday party and that James Rhodes had procured the Iron Man Mark II for the military, he offered up various weapons to augment the latter's armor. Hammer eventually discovered that Vanko was secretly siphoning company resources for his own armor. Hammer was so angry that he placed Vanko under house arrest. But Vanko freed himself, hanged his guards, and took control of the drones and the new War Machine armor when Hammer was unveiling them at the Expo, ordering them to target Stark. As he tried to regain control of the situation, Hammer was confronted by Pepper Potts and Natasha Romanoff, who demanded to know where Vanko was. When Hammer tried brushing them off, the latter grabbed him and forced him to reveal Vanko's whereabouts. Potts then called the police to have Hammer arrested for his complicity with Vanko. As he was being led away Hammer promised, "This isn't over." He was subsequently taken into S.H.I.E.L.D. custody.
Character traits
Justin Hammer is a cocky and ambitious man, who is jealous of Tony. He claims to be a scientific genius but in reality only disposes of a large amount of money who allows him to hire brilliant inventors. His main aim in life is to surpass his old time rival Tony in every possible field, but he lacks Stark's genius intellect, style, and popularity. He's arrogant enough to hire criminals like Ivan Vanko to reach his goals, being sure to be able to control them.