Sebastian Stan is a Romanian-born American-raised actor, who is best known for his television roles as Carter Baizen in The CW teen drama series Gossip Girl from 2007 to 2010, Jonathan "Jack" Benjamin in the NBC serial drama series Kings in 2009, and portrayed Jefferson/Mad Hatter in the ABC's fantasy drama Once Upon a Time in 2012. He also starred as Thomas "T.J." Hammond in the USA Network drama miniseries Political Animals in 2012.
For Disney, he played James "Bucky" Barnes/Winter Soldier in the 2011 film, Captain America: The First Avenger, based on the Marvel Comics character. Stan reprised the role in Captain America: The Winter Soldier, Ant-Man, Captain America: Civil War, Black Panther, Avengers: Infinity War, Avengers: Endgame, The Falcon and The Winter Soldier, and What If...?. He will portray Tommy Lee in the Hulu biographical miniseries Pam and Tommy.
- Sebastian Stan was originally shortlisted for the role of Captain America in Captain America: The First Avenger,, but Chris Evans was cast instead. Stan ended up portraying Captain America's best friend, James "Bucky" Burnes/The Winter Soldier/The White Wolf, who played a major role in the film's sequels, Captain America: The Winter Soldier, Captain America: Civil War, and many other films in the Marvel Cinematic Universe.
- Sebastian Stan was uncredited for his cameo in the post-credits scene in Ant-Man.