Sebastian Stan is widely recognized for his role as Bucky Barnes in the Marvel Cinematic Universe (MCU). His character first appeared in Captain America: The First Avenger (2011), establishing a fan-favorite narrative arc that characterized Bucky as a loyal friend turned conflicted soldier. Bucky Barnes has evolved significantly throughout the MCU, making notable appearances in films such as Captain America: The Winter Soldier (2014) and Avengers: Endgame (2019).