WHEN VH1 recently polled its viewers about the most shocking moment on its massively popular "Behind the Music" series, the winner -- or possibly the loser -- was tarnished teen idol Leif Garrett's tearful 1999 reunion with former best friend Roland Winkler. Twenty years earlier, a drunk and Quaaluded Garrett had driven off the Hollywood Freeway, rolling down an 80-foot embankment in a crash that left Winkler paralyzed from the waist down.

The episode was one of the highest-rated and most popular ever for the series, repeatedly airing the tawdry details of Garrett's personal tribulations in the wake of the accident. It traced a downward spiral of alcoholism, heroin addiction and depression, underscored by career setbacks that turned the one-time heartthrob into a jokey cultural reference.

"I'd actually never seen the show when they asked me to do it," says Garrett, who, not long before, had succeeded another former teen idol, David Cassidy, as host of VH1's "8-Track Flashback." VH1 sent Garrett some "Behind the Music" episodes, so the show's modus operandi -- tracing the inevitable rise and fall of Star X, with a public airing of sins and scandals -- could hardly have been a surprise. Indeed, Garrett admits he had serious reservations.

"But it just made sense," he says. "For one thing, I was thinking about this being the last time that I will address all these issues -- not just Roland, but everything and anything. It was an opportunity to get information out to a lot of people in a single telling, tell my side as I believe it to be, let people know that I'm actually still out here and doing something. It was the right timing with what I was doing then with my band, Godspeed.

"It's all steppingstones to here and now. It's all been good."

It's also been rough. Godspeed imploded and, after having insisted on VH1 that he'd been drug-free since a 1996 intervention, Garrett was arrested a few months after the show first aired for possession of heroin and cocaine; he pleaded guilty and entered a drug rehab program. Part of Garrett's downslide could be attributed to the death of his long-time girlfriend from a congenital heart condition. Garrett says he's been clean since then.

If Garrett's life hadn't been "Behind the Music" material, it could have been "E! True Hollywood Story." Which would have been a natural for Leif Per Garrett: It's where he was born Nov. 8, 1961, the son of struggling actors. He started acting at age 5. Three years later, Leif (pronounced Lafe) landed a small role in Paul Mazursky's "Bob & Carol & Ted & Alice"; among a dozen other films, he appeared in three "Walking Tall" movies with younger sister Dawn Lyn as the children of legendary lawman Buford Pusser. There were various TV guest shots and, in 1975, Garrett got his first starring role on the CBS series, "Three for the Road."

That show lasted less than a dozen episodes, but a toothsome, tousle-haired Garrett sparked a strong response among young female viewers and quickly slipped into the pages, and then onto the covers, of Tiger Beat, Teen Beat and 16 Magazine. The sacks of mail that started arriving at the studio suggested Garrett might be a marketable commodity.

"Nobody ever came up to me and said, 'Hey kid, can you sing?' " he recalls. "It was just, 'Hey kid, do you wanna make a record?' They already had their marketing down: I was the full California image, a blond, somewhat androgynous-looking pretty boy, a full-on skateboarder and surfer, actually living that lifestyle."

Unimaginative remakes of the Beach Boys' "Surfin USA" and Dion's "Runaround Sue" and "Wanderer" turned the 15-year-old Garrett into a minor hitmaker with major fandom.

Garrett says he wasn't particularly aware of the teen idol phenomenon, not even immediate predecessors David Cassidy and Bobby Sherman, much less the Fabians and Frankie Avalons of a generation before. "I never really paid attention to that stuff. I liked the British Invasion stuff -- Led Zeppelin, the Who, the Rolling Stones and all that sort of stuff."

Still, there was an underlying awareness that he and teen idol peers Andy Gibb and Shaun Cassidy were in for the short haul.

"Even when I was in it and it seemed enormous, I knew that there is no longevity to the teen idol business," Garrett says. "The kids that are digging your music -- and I was the age of the people buying it -- it's a pubescent thing where you have sexual fantasies, but when you get a boyfriend and your music tastes change, you don't listen to that person anymore. It's a short period of someone's life."

And, yes, he caught some of "American Idol," which left him both fascinated and fearful for the participants. "It's weird, I guess it's a new way of starting the teen idol machine up, and it's still going strong. The difference between now and then is that it takes five of them now, as opposed to one. Me, David, Shaun and Andy were the last of the solo idols -- now it's a group."

In 1978, Garrett would have his biggest hit, a disco ditty titled "I Was Made for Dancin'," but he was ready to hang it all up, frustrated with a musical straitjacket that was getting unbearably tight.

"I just didn't like the music and what I was doing," Garrett says.

Then, three days before his 18th birthday, Garrett's life changed with the crash that left Winkler a paraplegic. Though he promised to care for his best friend, Winkler's family filed a negligence suit, eventually winning a $7.1 million judgment; that legal battle left Garrett and Winkler estranged until VH1 orchestrated their reunion. Garrett and Winkler have remained in touch.

The singer's career went downhill quickly -- his last album was 1981's "My Movie of You" -- and his first career, acting, proved no refuge. Things could have gotten better when Garrett was cast in Francis Ford Coppola's 1983 gang film, "The Outsiders"; other young actors with supporting roles in that film included Tom Cruise, Patrick Swayze, Rob Lowe and Emilio Estevez. But Garrett's character was killed off in the first few minutes, a fate he might have wished on himself in such forgettable '80s fare as "Cheerleader Camp" and "Party Line."

Garrett recently gave it another shot with a role in David Spade's "Dickie Roberts: Former Child Star." Spade plays a washed-up, highly eccentric former child actor who hires an entire foster family to re-create the family and childhood he never had. Garrett plays one of Dickie's pals and wrote the theme song.

Chalk it up to being back in the public eye after "Behind the Music." Garrett's been on an assortment of shows, from "MTV's Loveline" and "Suddenly Susan" to a celebrity charity edition of "Weakest Link." There was even a scene in the animated series "Family Guy," in which family dog Brian sits on a couch watching "Behind the Music's" emotionally wrenching reunion, mouthing along word for word (a game Garrett supplied the voice-over himself after VH1 asked for too much money).

The music was already back in motion with Godspeed, which released a 1999 EP with guest guitarists Zim Zum (Marilyn Manson) and Dave Navarro. After that band broke up, Garrett toured briefly with grunge-punkers the Melvins, guesting on several songs, notably Nirvana's "Smells Like Teen Spirit" (the recorded version is on the Melvins' "The Crybaby" album).

Now Garrett's on the road again with F8 (a play on the word fate), which he describes as a hard-rocking mix of Led Zeppelin, Stone Temple Pilots and Alice In Chains. Having written only one song on his five albums, Garrett now writes most of the lyrics for F8, who offer an EP at venues and on their Web site while waiting for what the singer calls "the right deal.

"I want to make sure we get money to promote us," says Garrett. "I don't want them just to think that from my past name and what I do now with my acting, that that's going to sell records. I'm ready and willing and want to promote the hell out of it and send it to the level I think it deserves."

And, curious fans want to know, what's with the ever-present bandanna?

Garrett, who still lives in Hollywood, says simply, "I think it's more rock 'n' roll than my hairline."

LEIF GARRETT -- Appearing with F8 Friday tonight at Jaxx. * To hear a free Sound Bite from Leif Garrett, call Post-Haste at 202-334-9000 and press 8101. (Prince William residents, call 703-690-4110.)

Leif Garrett, with the rocking head covering, wants people to look at F8's music, not behind it.