NOTE: This article is about the incarnation of Justin Hammer from the Marvel Cinematic film series. The mainstream version can be found here: Justin Hammer (Marvel).
I took stuff, how does that make you feel? Does it make you feel bad? Good, BECAUSE THAT'S HOW I FEEL!!
~ Justin Hammer to Ivan Vanko
What I saw you did to Tony Stark on that track, how you stepped up to him in front of God and everybody, that was... WOW!
~ Justin Hammer explains how he was impressed by Vanko's intimidation and destruction at Monaco
Justin Hammer is a recurring antagonist in the Marvel Cinematic Universe, serving as the secondary antagonist of the 2010 Marvel film Iron Man 2, and a minor antagonist in the 2014 short film All Hail the King. He is Tony Stark/Iron Man's business rival and the owner of Hammer Industries.
In that version, Justin Hammer was portrayed a little different compared to the comic book version: Justin appeared to be younger than Tony Stark instead of being older, he whined when he didn't get his way, and appeared to be less intelligent.
Hammer was one of Tony's rivals. He owned Hammer Industries, a company that made weapons similar to those of Stark Industries. Hammer had been trying to create an exact replica of the Iron Man Armor, but in the process, injured just about everyone who tried the suit.
After he and his assistant Jack witnessed Iron Man fight Whiplash, Hammer was impressed with Whiplash and planned to break him out of prison, while at the same time place a fake Whiplash to take his place so that they could perform a fake death.
Hammer and Whiplash made a deal with each other that if Ivan made a huge army of drones (known as Hammer Drones), they would use them to put an end to Tony's career. What Hammer didn't know was that Whiplash was planning to turn against him and destroy Tony with the drones.
During the unveiling of the Hammer Drones, Hammer is confronted by Tony, who has known of Hammer's true allegiance with Whiplash. However, Whiplash activates the Hammer Drones to attack the entire area, forcing Tony to use his Iron Armor to fight back. When Pepper Potts (Tony's girlfriend and temporary CEO of Stark Industries) found out that Hammer was working with Vanko, she called the cops on him.
Natasha Romanoff also forced Hammer to reveal Whiplash's current location at Hammer's building, where she finishes off several of Hammer's guards before finding out that Whiplash has escaped to fight Tony. Following Whiplash's death and the destruction of the Hammer Drones, Hammer is arrested for his crimes, and he vows revenge on Pepper for this.
All Hail The King
In the short film, Hammer is held a prisoner in Seagate Prison. During the end credits, he is seen watching Trevor Slattery (the actor who had been hired by the deceased Aldrich Killian to impersonate the Mandarin) in the prison cafeteria being admired and fawned over by other inmates. Unlike the other inmates, Hammer remarks that he doesn't understand Slattery's appeal and isn't impressed with him at all.
Hammer giving Vanko a tour inside Hammer Industries HQ.