Colin Haley is hanging out with his parents in the living room of their $900,000 home, in an upscale suburb on Mercer Island, near Seattle, explaining to me why he's not likely to get killed climbing mountains.

"I think people see the risks that I take as greater than they are because they don't see the thinking behind them," he says, sitting in an armchair while kneading a cat. "For example, when I tried intravenous heroin, it wasn't like I was drunk at some party and someone was like, 'Do you want to shoot up?' and I was like, 'Oh, sure!' I researched online what a safe dosage is and how to know a needle is totally sterile. It wasn't some rash decision."

We've been on the subject of Colin's rapid rise as a world-class alpinist—at only 24, the University of Washington senior has already established himself as a major talent, with half a dozen cutting-edge climbs in Alaska, Canada, and South America over the past two years. By definition, that means he's pursuing very dangerous objectives, but Haley's parents have always encouraged their son to find his own limits, so their reaction to his drug analogy comes as no surprise. His father, Jeff, gets a thoughtful look on his face and chimes in with this: "I think your first experience was safer than my first experience."

His mother, Misty, salt-and-pepper-haired and effervescent, turns to her son, sounding concerned. "I thought that was your only experience," she says.

"Well," Colin says with a wry grin. "That was my only experience other than the time I took heroin through the nose."

Misty pauses a moment to probe her memory. "Oh, right," she says, relieved.

IT'S PROBABLY NO ACCIDENT that one of the most precocious young climbers around emerged from this creative and unorthodox family. Jeff Haley, 59, is a bookish-looking former patent attorney and advocate for progressive drug laws whose hobbies range from mountaineering to contra dancing. He's also a garage inventor, most successfully of CankerMelts, a mouth-sore medication that sells at Rite-Aid. Misty, 62, was a world traveler who bounced between various legal-field jobs; she's now a psychotherapist, counseling domestic-violence offenders and performing court-ordered parenting evaluations. "You know, like total crazy parents," she says.

Though Colin has sworn off drugs and alcohol to stay in peak condition for climbing, his adolescent partying was never discouraged. "Colin learned to determine his own boundaries, to find out what he can do, to test his skills from the time he was crawling," Jeff says. "Drugs are part of reality. You can't deny that part of reality and raise people who are adjusted to reality."

The family home—the staging area for this carnival of eccentricity—is spacious, light-filled, and distinctly informal. "Does it smell like cat pee in here?" Misty asked, beaming, when she first greeted me in the living room. "Tell me the truth." It did, but no one cared. The Haleys seem to revel in their quirky dishevelment. The kitchen counters are piled with dishes; the carpet has been grimed by a parade of pets.

Colin's room, which he shows me a few minutes later, is a striking contrast. He lives in a backyard toolshed that's been converted into a pair of 120-square-foot lofts for Haley and his 26-year-old brother, Booth. Colin sleeps on a musty mattress on the upper floor, and nothing is out of place or extraneous. The walls are decorated with pictures of forbidding peaks, like Cerro Torre and Nanga Parbat, and a bookshelf is crammed with mountaineering texts and neatly organized climbing magazines. There's no heating or plumbing. Blue light filters onto Haley's desk through a stained-glass image of K2, giving the room the aura of a shrine. "It's pretty nice for a hut," he says with pride.

The hut exemplifies the minimalism that defines Haley's style and hints at the tremendous self-discipline that has made him one of the most exciting newcomers in years. "I want to be climbing at the cutting edge of the sport, climbing routes that are pushing the boundaries, if even just a little bit," he says. Veteran climbers who've had an eye on Haley since he burst onto the scene in 2006, with the first ascent of an extreme, 7,500-foot face on Alaska's Mount Moffit, say there's little reason to doubt he can accomplish everything he has in mind. "He's far and away doing harder things than most people his age, or ten years older than he is," says Alaska climbing legend Jack Tackle, 55. "I can't think of anyone else right now, at such an early age, who's got as much under his belt."