Iron Man 2
He first appeared in Iron Man 2 where Tony Stark, Rhodes, Pepper Potts, Phil Coulson and Justin Hammer attend a hearing to try to get Tony Stark to hand over his Iron Man armor due to the potential threat it poses but Stark refuses then turns to Justin Hammer, and eventually was forced to award Stark and Rhodes a medal after he defeated Whiplash, which Stark took much pleasure into.
He reappeared briefly in Captain America: The Winter Soldier, where he was seen having lunch with SHIELD agent Jasper Sitwell, after the meeting he whispered "Hail Hydra" into Sitwell's ears. Secretly, however, both of them were HYDRA agents. He later appeared again near the ending, where he ended up arrested by various black suited FBI agents, due to his HYDRA membership being exposed thanks to Fury and Black Widow's leaks.