Mark Richard Hamill (; born September 25, 1951) is an American actor. He is best known for starring as Luke Skywalker in the Star Wars franchise in the original and sequel trilogies as well as his portrayal of the Joker in various animated DC Comics projects, commencing with Batman: The Animated Series in 1992.

Through the 1980s, Hamill distinguished himself from his role in the original Star Wars trilogy by pursuing a theatre career on Broadway, starring in productions of The Elephant Man, Amadeus and The Nerd. His other live-action film and television roles include Kenneth W. Dantley Jr. in Corvette Summer (1978), Private Griff in The Big Red One (1980), Crow in Sushi Girl (2012), Ted Mitchum in Brigsby Bear (2017), and Arthur Pym in the Netflix miniseries The Fall of the House of Usher (2023).

Hamill has also had a prolific career as a voice actor. Aside from Joker, his other voice roles include the Hobgoblin in Spider-Man: The Animated Series (1995–1998), Fire Lord Ozai in Avatar: The Last Airbender (2005–2008), Mr. Salacia and Senator Stampingston in Metalocalypse (2006–2013, 2023), and Skips in Regular Show (2010–2017).