Sean Penn is an American actor, director, and political activist. He is best known for his roles in films such as Mystic River, Milk, and Dead Man Walking. He has won two Academy Awards, one for Best Actor in 2003 for his performance in Mystic River and one for Best Actor in 2009 for his performance in Milk. He has also been nominated for several other awards, including Golden Globe Awards and BAFTA Awards. Penn is considered one of the most influential actors of his generation.