This spring, Penn won the Oscar as Best Actor for his role in "Mystic River." When Correspondent Charlie Rose caught up with Penn last fall, this 44-year-old actor and director was continuing to evolve as both an artist and person.
We've been watching his face now for more than 20 years: that get-out-of-my-face face, that in-your-face face, that don't-give-a-damn face.
Penn has been the face of spaced-out jazzman Emmit Ray in "Sweet and Lowdown." He's been the face of killer Matthew Poncelet in "Dead Man Walking," and the face of a retarded single parent in "I Am Sam" - all of them Oscar-nominated performances.
After early years as a stage actor and method-acting student, Penn's now been in more than 30 films, and has directed three more. But he tells Rose he believes his career is just beginning.
"I'm right now where I thought I was gonna start. I saw myself in little theaters 'till I was 40, looking, sitting at makeup tables backstage, getting ready to go on stage, looking down at Levis and a pair of rough-out boots before putting on my wardrobe," says Penn.
"And with my head hung, just trying to get relaxed before going on stage. And that I would get into the movies at about 40. That's what I thought was gonna happen."
Growing up in Southern California, Penn just wanted to be a surfer, which he got to play in his breakout film, "Fast Times at Ridgemont High."
In surfing terms, how would Penn describe this point in his life?
"You know, if you go out in a heat of surfers, somebody's gonna take off on a wave and then if the next wave is a bigger, better wave, then the next person's gonna score higher," says Penn.
"A lot of it is timing. I don't know that there are such things as accidents. But I think that, you know, I've found a stronger voice lately. And that has a lot to do with all kinds of elements coming together."
And it is coming together in a big way - so big, that Penn is now being acclaimed as one of the finest, if not the finest, film actor of his generation. And one of the reasons is his Oscar award-winning performance in "Mystic River," a dark, disturbing film about child abuse, loyalty, revenge, and the murder of Penn's teenaged daughter.
"He read the script. He called me back and said, 'This is a beast.' But he said, 'I love it,'" recalls the film's director, Clint Eastwood. "He has an ability to involve himself in the character that you see rarely."
What was the hardest scene for Penn to shoot?
"It was the scene where myself and Kevin Chapman are approaching the crime scene. So, I said to Clint, 'Look, if a couple of guys put their hands on me, somebody's gonna get hurt ... I'm gonna do everything I can to get to my daughter.' And so he said, 'OK'. And that was it. I figured OK, I'm just trusting Clint Eastwood," says Penn.
"And we started the scene, and before I knew it, there were about 18 policemen on me. And there wasn't a muscle in my body that could move. There was nothing I could do to hurt anybody. By the end of two takes of that, I was ready for an oxygen tank, but nobody got hurt and I got to go as far as I wanted to go."
And he also got as far as he wanted to go in the movie "21 Grams" which, like "Mystic River," is about guilt, regret, and revenge.
Penn has been described as a "relentless malcontent," "a guy who has more rage in him than you can imagine." Where is all of this coming from?
"I deeply believe that, you know, the level of rage that I have is shared. That everyone has it in some way," says Penn. "It's a great outlet. If you observe that and accept that it's there, and if you feel for it in other people, to be an actor. I don't believe that you can disconnect, that you can detach from the things that hurt people."
Has he changed since becoming a father?
"Yeah, a lot. I don't know if it's come with age or if you just get too damned tired of it. You know, he's just so tired of fighting," says Penn's wife and frequent co-star, Robin Wright Penn. "He's a loving nightmare. It's a beautiful torture, you know?"
Months before the U.S.-led coalition invaded Iraq, Penn went to Baghdad. He had nothing but harsh words for the Saddam Hussein regime. But in full-page ads in several major newspapers, he implored the Bush administration to give U.N. inspectors more time to discover any weapons of mass destruction, or any immediate threat to the United States.
He insists he is neither a pacifist nor an activist, but he felt that a preemptive strike on Iraq was an abuse of U.S. power.
"If we're gonna do it we'd better get really clear what it means, why we're doing it. Really, really clear why we have to do anything," says Penn.
"They found no weapons of mass destruction. They found no connection between Sadaam Hussein and 9/11. They found a lot ... they found none of the things that were initially in the sales plan."
Did he, for a moment, realize that the critics would come after him?
"I knew the criticisms that were gonna come. I knew the rage that was gonna come. You know, there's been a huge attack, you know, the ownership, the idea of patriotism," says Penn. "And you know, this is one of the things that I'm most concerned about. You know, if you speak up, you're anti-American. Well, that is un-American."
Un-American is what they once called Penn's late father, Leo, a hugely successful film and TV director who was blacklisted in the 1950s, and wrongly accused of being a communist sympathizer.
"He was a person who had so little bitterness. Having fought for his country, come back full of medals. Many times risking his life. Being shot down twice, just barely making it back across allied lines," says Penn. "And within a few years of that, the country he fought for said you can't (work) in this country because you're anti-American, a communist sympathizer."
But Penn says his father never lost his faith in America. Does the father now live in the son? "I hope so," he says.
Penn says he'd like to take a year off to just think about things. He says he might return to Iraq sometime soon. And he flirts with the idea of pursuing his burgeoning career as a director and quitting acting altogether - an idea that troubles his "Mystic River" director.
"I think probably at this particular time and of his generation of actors coming up, he's probably the very best," says Eastwood.
"Some part of you always wants to be the best that you can be, and to take compliments well and to accept people's feelings, especially when they're positive," says Penn. "But, it's obviously nice. It's better than getting kicked in the ass."