PASADENA, Calif. — Jeremy Piven was 37 years old when he was anointed with “The Fresh Face of the Year” acting award. At that point he’d been performing for 29 years.

He’d co-starred in nearly 40 movies and negotiated TV series like “Ellen,” “Cupid” and “The Larry Sanders Show.” But his wasn’t a household name. “I was a late bloomer compared to other people,” he said. “But for me it was the right journey.”

Piven grew up in the theater. His parents ran their own theater company in Chicago and Jeremy had trekked the stage since he was 8.

He thought everybody’s life included curtain calls and greasepaint. “I guess I lived in a microcosm. I thought everyone grew up on stage and everyone had an acting family — and you would grow up and do improv games and people would enjoy it. And then you would do some Salinger or some Mamet or some Chekhov. I literally thought everyone has this,” he said.

“Then I got to college and, ‘Wait a minute! Not everyone grew up in this.’ So that was a rude awakening. But … I guess ignorance is bliss. I didn’t know any better. You’re up on stage and you’re throwing yourself in, and I didn’t know enough to be afraid.”

It turns out he didn’t need to be afraid. He worked all of his adult years as an actor. And two years after he earned the dubious “Fresh Face” title, he landed the part of superagent Ari Gold on HBO’s “Entourage.” It was the role that boosted him onto the A-list.

“Some people call it paying your dues, and I just think it’s luck,” he said. “I got lucky in the way that it didn’t happen to me early on. I knew I was capable of doing other roles. I’d played these great roles on stage, but they weren’t necessarily coming to me (on screen). I didn’t even have the opportunity to audition for great roles.

“And Ari was a very small role, the reason I got it. It wasn’t on paper. It was one little scene in the pilot. He was supposed to be a fringe player. And I took a chance and I’m glad that I did. That was indicative of my career up till that moment, which was you take these tiny roles and you put everything you have into it, and hopefully they will grow. And they’ll see you’re contributing and maybe they will expand the role. So that was the result of a couple of decades of that type of work.”

It was more than luck, though, when Britain came calling, hoping to cast Piven as the gutsy American who established England’s famous high-end department store, Selfridges. As the bombastic, charismatic Harry Selfridge, Piven returns for his second season in PBS’ “Mr. Selfridge.”

There’s a difference, he says, between the way the British cast a role and the way the Americans do. “I think in the states it’s almost like the casting directors are ‘Method.’ They want to find the authentic person who IS the role. And I think in the U.K., if they do something, they’re going to do it right. So they go to drama school and log the hours and put the time in so they find the actor to PLAY the role. … And it’s very flattering for people to think I might be Ari Gold, when there are people like that. … People meeting me say, ‘Who’s THIS guy? And why are you so calm? Are you stoned?’ So that’s an interesting journey.

“And the Brits get that. I think that’s why I was cast in this role. I think they saw me play these various roles. I was lucky enough and the word is — I believe them or I hope this is the case — that I was the first person they came to. They thought I was capable of playing this role. And I was very flattered to play in a period drama and play this guy who’s an American entrepreneur not unlike Ari. But they’re very different people. Very different.”

Piven, 48, says there’s usually no time to ruminate about a role. “There’s always that moment where you question how you’re going to go about doing it, and then you just have to throw yourself into it,” he said, smashing his fist against the air. “You really do. I was lucky enough to study Commedia dell’arte with the director Tim Robbins who taught me the form which has really set me free. And part of that form as an actor is to throw yourself immediately into one of four emotional states: happiness, anger, sadness, fear. And you can’t think about it. You just DO it. And part of that acting technique has kind of informed and fueled me as a creative person. So I think it’s best to not get in your way.”