Michael Cera always seems to be pining for something: booze and a popular classmate in "Superbad"; the sly soul mate he impregnated in "Juno"; a lovely but forbidden cousin in TV's "Arrested Development."

One thing the modest, soft-spoken Cera does not pine for is celebrity, but he's got it anyway. As Hollywood's favorite awkward teen, Cera has just turned 20 with an enviable list of hits and critical favorites behind him.

He's back in full heartache mode in "Nick and Norah's Infinite Playlist," starring as a high school senior whose obsession over a shallow ex-girlfriend vanishes during an all-night romp through New York with a new dreamgirl (Kat Dennings).

With back-to-back $100 million hits in "Superbad" and "Juno," Cera has quietly jumped to the forefront of young Hollywood actors. He has two movies due out next year and another starting production soon in Toronto, near his hometown of Brampton, Ontario.

Steady, enjoyable work, not stardom and commercial success, is what he aims for, however.

"I never really had expectations either way. It doesn't matter to me. I just like the work," Cera said in an interview at the Toronto International Film Festival, where "Nick and Norah" premiered. "I like being on the set and that's what's important to me about being an actor. Things change and come and go, and whatever happens happens. As long as I like it and I'm working with people I like, I'll be happy."

"Nick and Norah" is a boy-meets-girl story that plays out over one wild night. The film opened Friday and had a successful weekend at the box office.

Cera's Nick is so smitten with his ex-girlfriend he devotes endless hours to making and packaging music compilations for her, CDs she thoughtlessly discards. But they have magically found their way to Dennings' Norah, who adores the song selections.

After Nick and Norah share a memorable introduction at a club, they wind up on a quest to find a missing drunken friend while dodging their past romantic partners, at the same time tracking the next guerrilla gig of their elusive favorite band.

It's the second all-nighter Cera has pulled on the big-screen, following last year's "Superbad," which followed the adventures of three underage pals on a hunt for alcohol.

"The one-night idea, I think it's something that people like. Whenever people go to a party or something, they're kind of hoping it will be a memorable night," Cera said. "It's a cool idea. Those nights are great when things just keep happening and leading to other things. It just feels like you're living."

Cera got into acting as a child after he and a friend enrolled in a class that taught improvisational games. One of the teachers told Cera's mother that the family should get an agent for the boy.

After doing some commercials, Cera began landing TV roles in Canada and then Hollywood, eventually winning the part of hemming-and-hawing teen George-Michael Bluth on the critically adored comedy "Arrested Development," the story of a dysfunctional rich family trying to make do after their assets are frozen.

Despite iffy ratings, Fox stood by the show for three seasons, though fans still mourn its early demise.

There has been buzz about a big-screen version of "Arrested Development," though Cera was uncertain if it should be resurrected.

"It would have to be really special, I think, to be worth doing, because I think the show is a nice story that ended nicely, and I'm scared of the idea of disrupting that," Cera said. "It's nice to end on a high note and get out early. It's kind of an instinct, you know. Keep them wanting more."

On "Arrested Development," Cera copped a nicest-kid-in-the-world demeanor, playing a lovably gawky teen who's impossible not to like.

Cera has perfected the persona in film roles, turning self-effacing decency into a surprisingly appealing trait in a business that often looks for glib wisecracking in its stars.

"He's just got a goodness inside him that you can see," co-star Dennings said. "I'm sure there are tons of people with goodness inside them, but you can't see it. With him, you can taste it. When you look at him, you just know that he's a good person.

"I think it's been so long since there was a leading man who wasn't like the chiseled guy with the hair and the leather jacket. Girls, once you're over the bad-boy thing, you're over it, and you just want a nice person, and he's as nice as you can get."

"Nick and Norah" director Peter Sollett met with Cera before "Superbad" and "Juno" came out, and he had not seen "Arrested Development."

But he took an immediate liking to Cera, saying the actor's demure on-screen presence is much like his real-life persona.

"What you see is what you get. It's a testament to his acting that you don't really feel the switch go off. The fact that you can't perceive the moment where he's begun performing proves what a subtle performer he is," Sollett said. "There are examples of things in the movie that I didn't even notice when we filmed, because they're so subtle you can only read them in a close-up on a big screen. With hundreds of people in the audience, it gets a roaring laugh."

Cera is set to begin work on the action romance "Scott Pilgrim vs. the World," adapted from a graphic novel about a slacker forced to do battle with his new girlfriend's evil ex-beaus.

Next year, Cera stars as a teen chasing a dreamgirl -- and hoping to shed his virginity -- in "Youth in Revolt" and co-stars with Jack Black in "Year One," a comedy about two banished prehistoric pals on an epic journey.

"Everybody's got Michael Cera fever, including me," Black said. "He's so fun."

Nice as Cera is, Dennings said she would love to see him play a bad guy.

Would Cera ever try it?

"Maybe someday. It depends on the script and the director, to be honest," Cera said. "There are no parts that I can think of right now where I go, `Oh, I'll never play that.' It just depends on what it is and if it feels right."