From left, Jay Adriel, Stephawn P. Stephens, Michael J. Mainwaring and Austin Colby in “Smokey Joe’s Café—The Songs of Leiber and Stoller” at Arena Stage. (Teresa Wood)

Michael J. Mainwaring, 20, has so much star power he’s shakin’ wit it. It’s his legs, his shoulders, the way he moves his arms and how he belts out a song. It’s like he’s missing a hinge, physically and metaphysically, so he inhabits every bit of stage and turns up the electric.

After the opening night performance of “Smokey Joe’s Cafe, The Songs of Leiber and Stoller” at Arena Stage last month, castmate Levi Kreis says, his mamma gushed. “That boy’s a Tony winner, right there,” Kreis’s mother said of Mainwaring. And since Kreis himself is a Tony Award winner, she should know.

In a cast full of incandescent lights — including Helen Hayes Award winners like E. Faye Butler and Nova Y. Payton — Mainwaring has found his own shine. He’s the skid-row bum in “D.W. Washburn,” and he’s caught up in sartorial joy in “Shoppin’ for Clothes.”

It's not only a star turn for Mainwaring, it’s the turn that earned him his Actors’ Equity Card, which he has yet to sign.

“I don’t think to myself I want to be a star,” the Potomac native says. Performing is “just something I have to do. It's something I’ve had to do since I was 10 or 11 years old.” Back when he was listening to Broadway recordings by Ethel Merman and Patti LuPone, dancing around his house in his footie pajamas, playing Simba in “The Lion King.”

Actor Michael Mainwaring. (Courtesy Arena Stage)

For his “Smokey Joe’s” audition, he binged on Leiber and Stoller until it was coming out of his pores. Then Director Randy Johnson “was so inviting. He sees things others can’t see in people,” Mainwaring says.

He says he felt safe. “Safe enough to go certain places. I rehearsed ‘I (Who Have Nothing)’ and I broke down in the room.”

Sometimes he still cries, or he belts it out, or he moves lightly, as fluid as water, all over the stage.

“I feel whatever the music is doing,” Mainwaring says. “I’m still learning where that comes from.”