Born Ramon Estevez to Irish and Galician immigrant parents, Sheen swapped his country home for the bright lights of New York, apprenticing at Judith Malina and Julian Beck's Living Theatre.

His real breakthrough came as the amoral, charismatic killer Kit (still his favorite part) on the run with Sissy Spacek, in Terrence Malick's 'Badlands', in 1973. Sheen then concentrated on small screen projects before returning to the fray as the military assassin sent to terminate the command of a crazed Marlon Brando, in 1979's 'Apocalypse Now'.

Sheen rebounded from a heart-attack, while filming, with a renewed sense of what is important in life. He donated his $200,000 salary for his three weeks' work on 'Gandhi' (1982) to various charities, and his meeting with Mother Teresa while filming in India restored him to the active Catholicism of his youth.

Some of his more memorable work continued to develop his politician's persona, such as his creepy turn as the villainous populist of David Cronenberg's 'The Dead Zone'. He went on to become US President Josiah Bartlet in the celebrated TV series 'The West Wing' (1999 to 2006). He picked up six Emmy nominations for Outstanding Lead Actor in a Drama Series for his performance as Bartlet, in addition to a Golden Globe for Best Performance by an Actor in TV-Drama, and two SAG Awards for Outstanding Performance by a Male Actor in a Drama Series.

After 'The West Wing', Sheen continued to act in a range of roles including Jack in the 2006 film 'Bobby', directed by his son Emilio Estevez and starring Anthony Hopkins, Sharon Stone and Elijah Wood, to name just a few. He was nominated for a Golden Globe and Sag Award for his part. This was followed by Martin Scorsese's 'The Departed' (2006), which also featured Leonardo Di Caprio, Matt Damon, Alec Baldwin and Mark Wahlberg. In 2007, he appeared in 'Talk to Me' and one episode of 'Studio 60 on the Sunset Strip' before featuring in 'Man in the Mirror' in 2008.

Roles in 'Imagine That', 'Echelon Conspiracy' and 'Love Happens' followed in 2009 before a relatively quiet 2010 and 2011. 2012 saw him appear in 'The Amazing Spider-Man' as Uncle Ben, 'Seeking A Friend For The End Of The World' and 'Flatland'. Sheen has returned to television to play his real-life son Charlie Sheen's father in 'Anger Management'. 

He is known for his own robust support of liberal political causes. He also supports the Democrats for Life of America's Pregnant Women Support Act. In 2004, he campaigned for Democratic presidential candidate Howard Dean, and then later supported nominee John Kerry.