FROM THE FINICKY oenophile in Sideways to curmudgeonly cartoonist Harvey Pekar in American Splendor, Paul Giamatti portrays neurotic discomfort well. It wasn’t surprising to watch him shift nervously during the Q&A after a Seattle International Film Festival screening of the upcoming August release Cold Souls—a metaphysical black comedy in which an anxiety-ridden actor named “Paul Giamatti” literally unburdens himself of his heavy soul…and discovers it’s just a chickpea.

The following day in a quiet room at the W Hotel, the actor explained why being on stage at the Harvard Exit felt odd. “I used to go to that movie theater all the time,” he said. “I was saying to the guy working outside that they used to give out free tea 20 years ago.”

From 1989 to 1992, Giamatti acted with Seattle’s Annex Theatre, which took advantage of his knack for embodying eccentrics. “They did a sort of continuing soap opera thing every Saturday night,” he recalled, grinning. “And they had me playing some psycho—I was stalking a newscaster or something. I just did so much weird crap. But it was really fun working there.”

In person, Giamatti is hardly the Sideways bundle of nerves that’s spoofed in Cold Souls. But you get the feeling you could send him away obsessing over something. Affably rumpled, hands flying, he doesn’t shy away from processing his answers out loud, bit by bit, during an interview—especially if you ask if he’s been typed on screen as a guy agitated by the fact that he knows too much. Because he didn’t think that until you mentioned that even his Emmy—winning turn as John -Adams fits that mold.

“I worry that it’s me that’s changing it into the same thing every time,” he pondered. “It’s worrisome. I don’t know. But it’s funny, because then I do something like The Illusionist, which is my favorite thing I’ve done on film, and he’s not—well, actually, he is sort of that guy who knows too much. But he deals with it differently, that guy. He wasn’t falling apart.”

Giamatti’s still getting used to the public recognition that comes with a Hollywood résumé. “Oh, yeah, that’s a very odd thing to deal with,” he said. “I was okay being the ‘Don’t I know you?’ guy. But people knowing your name…is odd.”