Penn was born in Santa Monica, California, to the late Leo Penn (a film director who was blacklisted for refusing to testify during the McCarthy era) and Eileen Ryan, an actress. Leo Penn was the son of Jewish immigrants from Lithuania and Russia of apparent Spanish extraction, while Ryan (born Eileen Annucci) is a Roman Catholic of Italian and Irish descent. The Penn surname was originally Pi�on, but it was changed when his grandfather emigrated to the United States. Penn has one living brother, musician Michael Penn. Another younger brother, actor Chris Penn, died on January 24, 2006.

Penn launched his career with the film Fast Times at Ridgemont High in the role of Jeff Spicoli and has since starred in over 40 movies. He won an Oscar for Mystic River. Penn has also been nominated for three other Academy Awards in recognition of his roles in the films I Am Sam, Sweet and Lowdown and Dead Man Walking.

In 1991, Penn made his directorial debut with The Indian Runner, a film based on Bruce Springsteen's song "Highway Patrolman" from the Nebraska album. He has since directed two more films: The Crossing Guard in 1995 and The Pledge in 2001. Both of these films starred Jack Nicholson.

Penn is rumored to be in the running for the role of The Joker in the sequel to 2005's Batman Begins. Christian Bale allegedly let slip to a British Tabloid at the premier of Batman Begins that Christopher Nolan was courting the actor.

Penn's personal life began to attract much media attention when he married pop star Madonna in 1985. The relationship was marred by violent outbursts against the press intrusion into his life, including one incident for which he was arrested. Later in the marriage, Penn was charged with felony domestic assault. He later pleaded to a misdemeanor charge. After a divorce in 1989, Penn started a relationship with Robin Wright, with whom he had two children, son Hopper and daughter Dylan before they married in 1996. They live in Ross, California.

On April 10, 2003, Penn's 1987 Buick Grand National was stolen in Berkeley, California with two firearms in the trunk. Sean also has a 1968 Chevrolet El Camino.

Along with Johnny Depp and Mick Hucknall, Sean Penn is part-owner of the Parisian restaurant-bar Man Ray.

His younger brother, Chris was found dead in his Santa Monica condominium on January 24, 2006.

On October 18, 2002, Penn placed a $56,000 advertisement in the Washington Post asking President George W. Bush to end a cycle of violence. It was written as an open letter and referred to the planned attack on Iraq and the War on Terror. In the letter, Penn also criticized the Bush administration for its "deconstruction of civil liberties" and its "simplistic and inflammatory view of good and evil." Penn visited Iraq briefly in December 2002, largely eschewing meetings with the press.

He was portrayed in the war satire Team America: World Police (2004), which prompted the actor to send a letter critical of its filmmakers: Trey Parker and Matt Stone. The letter ends with Penn saying "Fuck you", which amused the filmmakers, who used the letter as a form of publicity to promote the movie.

On June 10, 2005, Penn made a visit to Iran. Acting as a journalist on an assignment for the San Francisco Chronicle, he attended a Friday prayer ceremony at Tehran University. [1]

In September 2005, Penn traveled to New Orleans, Louisiana to aid Hurricane Katrina victims. He was involved in several rescues, including 73-year-old John Brown, who had told his sister over the phone: "Guess who come and got me out of the house? Sean Penn, the actor. The boys were really nice." The actor then gave some rescuees an unspecified amount of money to tide them over, and then took those who were in need of medical attention to the hospital. Although Penn was praised for his rescue efforts, he was also criticized for bringing along a cameraman and Rolling Stone magazine reporter Matt Taibbi to document the event.

On January 7, 2006, Penn was a special guest at a forum hosted by the Progressive Democrats of America. He was joined by author and media critic Normon Solomon, Democratic congressional candidate Charles Brown, and activist Cindy Sheehan. The "Out of Iraq Forum" was attended by 200 individuals and took place in Sacramento, California. The program was moderated by Bill Dursten, President of the Sacramento Chapter of Physicians for Social Responsibility. The forum was held at a SEIU union hall and was organized to promote the anti-war movement calling for an end to the War in Iraq. Progressive activists, Democratic Party leaders, and other individuals gathered to demonstrate their impatience and frustration with U.S. involvement in Iraq.