Ram�n Antonio Gerard Est�vez (born August 3, 1940), better known by his stage name Martin Sheen, is an actor best known for his performances as Captain Willard in the film Apocalypse Now, Confederate General Robert E. Lee in the film Gettysburg (Gettysburg (film)), and President (President of the United States) Josiah Bartlet on the television series The West Wing. He has worked for some of cinemas most prominent directors, including Martin Scorsese, Steven Spielberg, Oliver Stone, Francis Ford Coppola, Richard Attenborough, Terrence Malick and Mike Nichols.

Along with the critical acclaim he has received as an actor, he has become known as an activist. Born and raised in Ohio, United States, with Irish (Ireland) and Galician (Galicia (Spain)) parents, Sheen is also an Irish citizen.

He is the father of actors Emilio Est�vez, Ram�n Est�vez, Carlos Irwin Est�vez (Charlie Sheen), and Ren�e Est�vez, and is the brother of Joe Est�vez (Joe Estevez), also an actor.