A friend who worked as an editor at Ms. magazine in its glory days once described Gloria Steinem as the nicest famous person she had ever met.

An interview years ago during which Steinem served me tea in her cozy Manhattan apartment did nothing to rebut that impression. At a recent conference where Steinem spoke, I was struck anew by her humility, her apparent conviction that — for all her celebrity and accomplishments — she still had much to learn from other women.

Emily Mann’s earnest documentary play, Gloria: A Life, conveys this ingratiating aspect of the feminist icon, not least because of its reliance on Steinem’s own writings.

Flashing back from the present, it touches on her undercover reporting as a Playboy bunny, her gradual political awakening, and her troubled childhood. It also spotlights her alliances with Cherokee activist and chief Wilma Mankiller, African American lawyer Florynce “Flo” Kennedy, and vividly brazen politician Bella Abzug.

Playing through Oct. 6 at Princeton’s McCarter Theatre Center, where Mann kicks off her 30th and final year as artistic director, Gloria is part character study, part feminist history (from a Gloria’s-eye view, with nary a mention of rival Betty Friedan), and part pep rally for contemporary activism. What it is not, its ambitions notwithstanding, is a particularly challenging or boundary-pushing piece of theater.

Still, for those who know little of the movement, the play is information-rich and sleekly presented by an all-woman ensemble, aided by Elaine J. McCarthy’s projections and Robert Kaplowitz and Andrea Allmond’s nostalgia-inducing sound design. It runs just under two hours, including a brief, expendable audience “talking circle.”

At its center is Mary McDonnell’s Steinem, with long hair, glasses, and black bell bottoms, accessorized by costume designer Jessica Jahn with a fringe vest, a shoulder-padded jacket, and other decade-defining tops. The Obie-winning actress captures Steinem’s Midwestern speech patterns, her niceness, and her bouts of self-doubt. She lacks only Steinem’s charisma.

Though admirably intimate, Mann’s in-the-round restaging of Diane Paulus’ original direction does McDonnell no favors. The actress has to keep swiveling around, and too often audience members arrayed along either side of Amy C. Rubin’s set — Oriental rugs dotted with throw pillows, stacks of books, and a few pieces of furniture — glimpse just McDonnell’s back.

The gender-bending ensemble (all ably assume a variety of roles, and Gabrielle Beckford is particularly arresting) enlivens the show, and video clips, including some of the performers themselves, lend it a larger-than-life quality.

The intent of Gloria: A Life is not to do critical history, but to serve as agitprop. Contrary viewpoints (the sexism of the writer Gay Talese, the disdain of Richard Nixon, the homophobia of Phyllis Schlafly) are presented only to be batted away.

No splits in feminist goals, strategies, or tactics — let alone the movement’s fierce personal infighting — receive any attention. Steinem’s late-life marriage, cut short by her husband’s tragic cancer death, is the only one of her many romances to figure in the drama.

At the show’s close, McDonnell urges audience members to “do at least one outrageous thing in the cause of social justice” by the next morning. Outside the theater, a man who’d spoken eloquently on behalf of women’s reproductive rights just minutes earlier shouted at me, “I love you!” It was, he declared, his “outrageous thing.” Not, I’m guessing, what Mann — or Steinem — had in mind.

THEATER REVIEW

Gloria: A Life

Through Oct. 6 in the Berlind Theatre, McCarter Theatre Center, 91 University Place, Princeton.

Tickets: $25-$83.50.

Information: 609-258-2787, mccarter.org.