After speeding back to stardom, Grey's Anatomy's Patrick Dempsey burns rubber through Atlanta.

He came from nowhere and was, for a brief moment in the 1980s, everywhere, as ubiquitous as narrow neckties and Madonna-bes - this inexplicable stud, this you-gotta-be-kiddin'-me lady-killer, this devil with the choirboy's face. First he was the dork who got the girl (Can't Buy Me Love), then the teenager romancing much older women (In the Mood), then the pizza boy delivering more than a slice to the likes of Princess Leia (Loverboy).

The dude was hot, likely to be the next Steve Guttenberg, the next Andrew McCarthy, the next Judd Nelson.

Alas, that's just what happened to Patrick Dempsey, who was everywhere and then nowhere at all - from tacked up to tossed out in the time it takes a Teen Beat reader to realize there's a hunkier hunk for the having. He never stopped working, but try telling that to anyone who drew a breath in the 1990s. It seemed as though Dempsey might be doomed to the fate of a trivia question: What former 1980s star appeared in three failed TV shows based on the hit movies Fast Times at Ridgemont High, The Player, and About a Boy? "It was a pattern developing that I needed to get out of," he says now.

Then, in the new millennium, he was resurrected, pulled from the has-been scrap heap and polished up to look brand-new. Suddenly, he was everywhere all over again. The screen had gotten smaller, but the gigs felt enormous. There he was on Once and Again (for which he received a 2001 Emmy award nomination for Outstanding Guest Actor in a Drama Series) and on the short-lived Karen Sisco, two defunct ABC series adored more than they were actually watched. And on Will & Grace, playing Eric McCormack's sportswriting boyfriend. And on The Practice, just before the firm was busted up. He got movies again: Sweet Home Alabama, in which he lost Reese Witherspoon to Josh Lucas (which never would have happened in 1987); The Emperor's Club, with Kevin Kline; and HBO's Emmy-winning Iron Jawed Angels, costarring with two-time Oscar winner Hilary Swank in a critically celebrated movie about the women's suffrage movement.

He was back, once more a salable commodity, perhaps never more so now that he's Dr. Derek Shepherd on ABC's outta-nowhere hit Grey's Anatomy, one of those midseason replacements so successful it knocked out of the starting rotation the once-formidable Boston Legal with Emmy winners James Spader­ and William Shatner. Adios, Captain Kirk; hello, Doctor McDreamy, as Dempsey's referred to on the show, in which his character has been known to take an out-of-gown tumble with Ellen Pompeo's Dr. Meredith Grey, for whom the show is named.

"Thank God Grey's Anatomy came along," Dempsey says now, grateful for the good gig, the good writing, the good paycheck. When he was cast a year ago, he says, "You're also just looking for a job, and then you're looking for a character that you're going to enjoy playing, if it does indeed go. But you're also trying to turn around preconceived notions of what people think you are or what you've done in the past, which sort of always follows you along."

But how, when your trail has disappeared for so long? Don't audiences lose the scent after a while?

"I think because of the nature of cable, a lot of these early movies just run and run and run," he says, with nary a hint of resignation in his voice. "Every time you turn the TV on, it's still on there, and that image is just stuck in people's heads. I'm just amazed at the impact Can't Buy Me Love has had on people."

Pardon, if you will, the laughter of the interviewer. It is meant with all due respect.

"There's something about the dynamic and the archetype of the character that people relate to," he says, not at all offended. "And it's just many generations now! It's interesting to see. … I think the perception of me changed starting with Once and Again, with people viewing me as an actor getting nominated for that, and then with Will & Grace - I was maturing, being a leading man, with people going, 'Oh, you're growing up, finally.' "

Grey's Anatomy (which was up for three Emmys this year) appeared at just the right time, and not just for Dempsey. Reality shows are being shoved to the margins, populated by the desperate and pathetic, as hour-long dramas make their welcome return to prime-time schedules and ratings charts, and ER slides further into medical-show mediocrity (which, perhaps, also accounts for the success of Fox's House, another doc drama with a good bedside manner). But the rapid rise of Grey's Anatomy guarantees nothing; today's smash is tomorrow's The Practice, after all. Creator Shonda Rhimes and her writers and directors will have to keep their characters from becoming caricatures - to resist the temptation to turn Doctor McDreamy into a pretty-boy punch line rather than a person.

"I wanted a character that was mature," Dempsey says. "A lot of great things were set up for me: I'm playing a neurosurgeon, which is immediately attractive and has been written for me to be Doctor McDreamy. But I don't want to be just that. Now that we've established that, we want to see what's the flaw behind this person - not the projection the world sees, but what's the reality behind it. What's the character flaw? That is going to be more challenging for me to play than just being the perceived hot doctor, because that's just boring. There's one note! You don't want to play the one note, and I think [it's crucial] that you keep challenging everyone and asking the question, 'Where are we going?' "