To master a language is to garner a kind of power: the ability to communicate one’s needs, share stories, explain who you are to another, and hear that you are understood. For P. Carl, who transitioned from living as a woman, Polly, to a man, developing the vernacular with which to share his true self with others was critical and profound. His journey, which includes years of deliberation, transformation inside and out, and joy, is detailed eloquently and with heart in “Becoming a Man” at the American Repertory Theater through March 10.

But changing from Polly (Stacey Raymond) to Carl (Petey Gibson), the man he always knew he was, impacted much, from his marriage to his writer wife Lynette, dating back to when he was Polly, to his relationship with his father and with the world. It was at a hotel, Gibson’s Carl tells the audience at the start of the show that he became a man, “soaking in all the sirs.” And it was exhilarating. It’s important to feel seen. It’s something we all crave to varying degrees. Carl puts it all on the line to achieve it.

The cast is full of accomplished thespians, though it’s the most fun to watch Justiin A. Davis (HBO’s “Boardwalk Empire” and Prime Video’s “The Boys”), who morphs effortlessly from Carl’s trainer to an old companion of Carl’s father and more, and Stacey Rome, who goes from portraying Carl’s mother to Lynette’s friend, who peppers Lynette with questions about her attraction or lack thereof to men.

The play is adapted from Carl’s 2020 memoir of the same name. A senior distinguished artist-in-residence at Emerson College in Boston, Carl has studied queer theory and worked at an AIDS hospice. Long before seeing the play, I’d come across his story in New York Magazine and was struck by the sincerity and candor. In it and in the play, Carl talks of times when he participated in the verbal jabbing at women — despite his history as a feminist and activist — that some men do. Carl doesn’t shy away from his body’s political and social implications.

Onstage, the show — written and thoughtfully co-directed by Carl and Diane Paulus — moves through multiple scenes of his and his wife Lynette’s life with the help of gorgeous projections depicting mountain vistas, the gym, and the highway signs of Ashtabula, Ohio, by projection designer Brittney Bland. As the story unfolds, it appears that as Carl emerges, Elena Hurst’s Lynette loses her footing and grieves what was of their decades-long union.

What’s most compelling are the conversations between Polly and Carl throughout out the show. When Carl gets to don the right bathing suit as a man and swim, Polly expresses jealousy, but as Carl’s marriage suffers, he seeks advice from his friend Nathan, a trans man, who points out the complexities of what’s happening. But it’s Polly who reminds Carl of the hard work it took to create and sustain this relationship and how Carl is messing it up.

The story is marked by visits in and out of psych wards, trauma, and more, but the narrative, like life, is lined with love, friendship, pain, discovery, and finally, euphoria. After living nearly 50 years as Polly, Carl must figure out what it means to be a good man and navigate the world as a good son and husband. It’s this work that anchors the illuminating play.

It’s courageous to tell the truth about oneself, even the bits that feel uncomfortable. And that, too, is another kind of power.

American Repertory Theater’s production of “Becoming a Man” runs  through March 10.