LET ME BE BLUNT: I'm no Jack Johnson groupie—his music just doesn't make much of an impression on me. But he's a skilled craftsman of infectious pop songs, and I've caught myself more than once singing along to one of his tunes on the radio.

Music critics have been less generous. Rolling Stone, after ignoring Johnson's 2001 debut album, Brushfire Fairytales, gave On and On (2003) just two stars out of five, complaining that Johnson's "Hawaiian surfer's croon evokes the mellow-yellow moan of Donovan but without the weirdness that made that psychedelic folkie compelling." Blender accused him of writing "lazy dorm-room poetry." A New York Times reviewer said of one of his 2005 concerts, "About half the show exuded a sleepy charm; the other half was much the same, only without the charm."

But one thing critics often miss with Johnson is something that doesn't necessarily come through the speakers: There's no act. "He's just Jack," as Rob Machado, one of his many pro-surfer friends, told me. "No matter what, he's going to be onstage in flip-flops and a T-shirt. He's just going to tell stories—and they're real."

Johnson has a knack for making even the most overt celebrity moments feel authentic, as I saw for myself when I met him earlier today in the rustic one-room house Malloy rents in Malibu. Johnson was using it for a photo shoot with Vogue, but the atmosphere was more Fourth of July barbecue than high-fashion showcase. As Johnson worked with the photographer, Malloy was out on the deck, grilling a fish for tacos. I sat on a step with Johnson's wife, Kim, and the two Johnson kids, along with a family friend visiting from New York, a guy who runs biodiesel stations in Los Angeles, and Johnson's publicist. All the while, Johnson was warm and attentive to his wife and kids, and seemed like part of the crew. There were no nannies, no deferential ass-kissing from the FOJs.

After we downed the tacos—served on brown recycled paper towels—we headed for the Brushfire building across town. "I can drive if you want to take notes," Johnson said as we walked up the driveway to my truck. I declined, and he folded his six-foot frame into the passenger seat. While we headed south on the Pacific Coast Highway, the ocean as calm as a lake and the charred hills still redolent of ash from the recent wildfires, Johnson recounted the now well-known details of his past: He grew up riding waves on the North Shore but chose studying film at UC Santa Barbara over a pro-surfing career. In 1999, he wrote a couple of songs for a surf film he produced with Emmett and Chris Malloy, then stumbled into fame after being noticed by Ben Harper's manager.

He also tried to explain the roots of his eco-sensibilities. Some of his best childhood memories, he said, were formed when the ocean flattened out and his dad took him to the outer islands off Oahu in a traditional Hawaiian canoe. "Those canoes are only as wide as your hips, as long as six people, and with just a little leg space between you and the person in front of you," he said. "Everything you'd bring would have to fit into that space. It couldn't spill over. You couldn't pay more to bring extra baggage." The material, in essence, was immaterial. "That's as happy as I'd ever been," he added. "It wasn't about being overloaded with Christmas presents."

It's that scale-it-back philosophy that Johnson's trying to bring to his music career—following a path, he's quick to point out, paved by musicians like Neil Young, Pearl Jam, and Willie Nelson.

"I'm not trying to act like I've got all the answers and that I'm greener than everyone else," he said as we turned onto a tree-lined boulevard. "I want to do what I can to help, but sometimes it starts to overwhelm me. It's hard, because as soon as you put your voice in there, all of a sudden you're the guy the newspaper wants to talk to. I accept the fact that I'm a somewhat known personality now and I like that I can use it for good things, but I ultimately don't want to run for president."