“I’m still learning how to be an actor in this world,” he said. “I just started to realize that there’s a way to do it that you’re not only just an actor playing parts — you’re doing something for yourself, and for other people, that can feel bigger.”

He and Ms. Thurber have been friends for nearly a decade. They bonded over their similar upbringings: his in Connecticut, hers in Massachusetts. “Coming from poverty, from a working-class family, with not as much access to education — you don’t find that many of us in the arts in New York City,” Ms. Thurber said. “Where we both come from, people don’t have a lot of options — you have manual labor, the military, dealing drugs. I recognize in Chris somebody who has found that there is a life-or-death quality to theater, an urgency.”

She sees him as a perfect complement to her work: “He just, on a cellular level, knows the people I’m writing about. He understands their rhythms, their movements.”

When Ms. Thurber and Rattlestick’s artistic director, David Van Asselt, approached Mr. Abbott last year about acting in one of the “Hill Town Plays,” he immediately agreed. And he threw himself into the process. “He comes to rehearsal even when he is not in the scene,” said Jackson Gay, the director.

Even before he decided to depart “Girls,” his character on the show was divisive. Charlie is “a soggy pushover,” one viewer wrote on Indiewire.

“The thing that most people have seen him in is not the color that is most present in Chris,” said Betty Gilpin, who plays Lilly in “Where We’re Born.” “For him to be written off as the ‘nice guy’ is an injustice in my mind. He’s got that bull in a china shop in him.”