The ubiquitous character actor is on the hottest streak in Hollywood.

So you want to make a hit movie. You’ve tried crowd-pleasing special effects, hung A-list names on your marquee, spent millions on a marketing campaign. And you still end up celebrating your gala premiere at Blockbuster’s direct-to-video bin.

Never fear. Next time, remember the secret of cinematic success: Paul Giamatti.

Since his big-screen breakout as Pig Vomit, Howard Stern’s bug-eyed nemesis in 1997’s Private Parts, this 31-year-old Yale-trained actor has become Hollywood’s hottest lucky charm, popping up for brief but propitious turns in one box office smash after another. He took a drag from Julia Roberts’ cigarette as a bellboy in My Best Friend’s Wedding, helped Ed Harris work the controls in The Truman Show, and tried to get Eddie Murphy not to talk to the animals as the evil psychiatrist in Dr. Dolittle. And this week—in his latest don’t-blink tour de force—he’ll spend a few moments with Tom Hanks on the battlefields of Saving Private Ryan. All together, it comes to about 15 minutes of actual screen time so far this year—but it will probably make Giamatti 1998’s highest-grossing actor.

“My agents were not crazy about me doing Ryan because it wasn’t a big part,” Giamatti admits, settling into a chair in the shabby-chic Manhattan loft he shares with his screenwriter wife, Liz, 34. “But I find these plain little characters fascinating. All the actors I like played those sorts of parts. Elisha Cook Jr., the weaselly guy who gets killed in The Maltese Falcon? I love him. Or Peter Lorre? Man, he was awesome.”

Giamatti’s own background is not quite as plain as his favorite characters’. His father, A. Bartlett Giamatti, who died in 1989, was president of Yale (“I had a very good in,” the actor says of his acceptance into the prestigious drama school) and later served as Major League Baseball commissioner (he kicked Pete Rose out of the majors for gambling). And while Giamatti’s un-chiseled looks don’t have autograph hounds chasing him around New York, he does have a knack for getting noticed on screen, even in his dinkiest parts.

“He reminds me of one of those character actors from the 1930s and ’40s,” offers casting director David Rubin, who hired Giamatti for his next small-but-notable role, playing the most memorable of Samuel L. Jackson’s hostages in The Negotiator, opening next week. “He has a specific, indelible look. You’re always happy to see him on the screen. That’s exactly what you’re looking for when casting supporting parts.”

Those supporting parts will soon be growing bigger. Giamatti will stretch in next month’s Safe Men, an indie comedy in which he’ll play a henchman for the Jewish Mob (named Veal Chop, no less). And later this summer he’ll begin his most ambitious part yet, playing Andy Kaufman’s best friend in Man on the Moon, Milos Forman’s much anticipated biopic starring Jim Carrey. “It’s so weird,” he says. “Just because I’ve had small parts in these big movies, people offer you more and more stuff. They get all these expectations for you. What if I suck in all these things? What if I just blow?”