Sebastian Stan (born August 13, 1982) is a Romanian American actor, known for his role as James Buchanan "Bucky" Barnes/Winter Soldier in the Marvel Cinematic Universe. He also appeared in the 2010 film Black Swan. On television, Stan portrayed Carter Baizen on Gossip Girl, Prince Jack Benjamin on Kings, Jefferson on Once Upon a Time, and T.J. Hammond on the miniseries Political Animals. His role on Political Animals earned him a nomination for the Critics' Choice Television Award for Best Supporting Actor in a Movie/Miniseries. In 2015, he co-starred in Jonathan Demme's Ricki and the Flash and Ridley Scott's The Martian.
Stan was born in Constanța, Romania. At age 8, he and his mother moved to Vienna, Austria, where his mother was employed as a pianist. Four years later, they moved to Rockland County, New York, after his mother married Anthony Fruhauf, the headmaster of Rockland Country Day School.
During Stan's years at the Rockland Country Day School, he starred in productions including Harvey, Cyrano de Bergerac, Little Shop of Horrors, Over Here!, and West Side Story. He also attended the Stagedoor Manor summer camp where he was cast in many camp productions. It was then that he decided to take acting seriously and began to apply for acting programs at several universities. He was accepted to and attended Rutgers University's Mason Gross School of the Arts, which also gave him the opportunity to spend a year abroad studying acting at Shakespeare's Globe Theatre in London, England.