And heartbreaking finality.
When Penn - an actor and director unafraid to put his views out there, whether about Katrina or Iraq - got hold of Jon Krakauer's book Into the Wild, he was rocked to his core.
"From the time I read the book, shortly after it came out in '96, I knew I wanted to make this movie," he says, dressed in natty black and camped in a hotel room on the afternoon that Into the Wild - which stars Emile Hirsch as McCandless - premiered at the Toronto International Film Festival.
"I tried for a long time. It took a long time for the parents to feel comfortable with the idea of a movie being made," Penn says.
But over meetings with Krakauer, and Walter and Billie McCandless, Penn made his case, gaining the father and mother's trust. Once he had their blessing, he set to work writing the screenplay - he didn't need to reread the book, he knew it that well. And then he set out on his own cross-country journey ("due diligence" he calls it), retracing McCandless' route - stopping at the same South Dakota farm, the same Oregon beach, talking with some of the same folks McCandless spent time with.
In the end, Penn found himself in the remotest precincts of the 49th state, having crossed three rivers, the Savage, the Sushana and the Teklanika, to arrive at the rusted bus that McCandless had made into his home.
"There were moments of sad reflection along the way," Penn says. "I wanted him to be there so I could ask him something. But I've lived with this story and [with] my response to Jon Krakauer's book 10 years before I started this project, and I came to realize that I'd been writing it in my head the whole time. . . .
"And the movie is the book to me. When you see the movie, that's what I read. In that sense, I was just a faithful adapter."
Faithful, and awe-inspiringly adept. Into the Wild, which opens Friday at the Ritz Five and Showcase at the Ritz Center/NJ, is Penn's fourth feature as a director. From his 1991 debut, The Indian Runner, to his most recent, 2001's The Pledge (with a spooky Jack Nicholson), Penn's movies are devastating little dramas with strong performances, dark emotions.
Into the Wild is something else: The canvas is bigger, the landscapes majestic, the cinematography by Eric Gautier extraordinary. Eddie Vedder provides a haunting song cycle. The supporting players - especially Hal Holbrook as a lonely old gent befriended by McCandless, and Catherine Keener as a flower child grown up and grown sad - are terrific.
And in Hirsch, a young Californian with tousled dark hair and a big smile, Penn found someone not unlike the cocky kid who played Jeff Spicoli in that early '80s teen classic, Fast Times at Ridgemont High.
"Yeah," Penn says. "If a director offered Into the Wild to me and I was in my 20s, I would have certainly jumped at the chance."
Instead, Penn began a long "sizing up" period with Hirsch, whom he had seen in the L.A. skateboarding movie Lords of Dogtown. "I called him and said I'd like to start having some meetings with you. And I met him - I kept it very vague over about a four-month period - while I was assessing whether this 21-year-old was going to devote himself on the level that he had to . . . coming to the conclusion that he had the talent as an actor.
"But did he have the will and the fortitude as a man? Of a boy-becoming-a-man? And I came to the conclusion that he did, a lucky conclusion at that."
Hirsch lost 41 pounds off his 156-pound frame in the production, notching his belt ever tighter as he portrayed McCandless in the snowbound taiga, hunting for food, eating roots and berries. The actor had to kayak down raging rapids and trek up desert hills loaded down with camping gear. There were no stunt doubles.
"Yeah, it was one of those experiences where the kid walks up to the edge of the diving board and peers over and it looks really high," says Hirsch, in a separate interview. "It's one of those things where you just have to jump, and hope that you aim your head into the water right."
After Penn gave him the job, Hirsch started a training regimen: running, climbing, weights. He thought he was ready. And then, in May 2006, they started shooting.
"One of the first days, Sean was absolutely relentless, having me climb up this hill," Hirsch recalls. "A crew guy tried to throw me some rope, and Sean was like, 'Don't throw him rope, you're trying to help him? Don't do that, no way!'
"And the rope disappeared. I went, 'Ohhhh, man.' That's when it dawned on me just how incredibly hard this was going to be.
"I had a conversation with a guy who had been in the Army," Hirsch continues. "I asked him about his experiences in boot camp, on the first couple of days, and he goes, 'Just look at it this way. You pushed it really far today and you're still here. Which means you can go even farther tomorrow. . . . And as all the chaos is going on, keep your eye on one little thing, one little detail that you think is beautiful. . . . And every so often you pick out that little thing, and that will be your peace."
Into the Wild, destined for Oscardom, is about a lot of things. It's about looking deep inside oneself, finding the quiet and the core. It's about rediscovering America, the roads far off the interstates. It's about making movies the way Terrence Malick and Francis Ford Coppola made them back in the 1970s. It's about fathers and sons, or surrogate fathers and sons. And it's about what defines a life, and defines a death.
"Someone asked me the other day," Hirsch says, " 'Is this a tragedy, or is this a film about an epiphany?'
"Well, the epiphany that he has at the end is a tragedy - the epiphany that happiness is only real when shared - because he realizes it too late."
And as for Penn, he wants to share his happiness, too.
"I love this movie," he says - and he has the right to. "I'm not going to say I'm not excited. But it's only real when shared, so I'm looking forward to getting it out there."
Contact movie critic Steven Rea at 215-854-5629 or firstname.lastname@example.org. Read his blog, "On Movies Online," at http://go.philly.com/onmovies.