In the 2017 movie “The Post,” Meryl Streep immortalized Washington Post publisher Katharine Graham in golden caftan glory as she made the historic and career-defining decision to publish the Pentagon Papers, documents about the secret history of the Vietnam War that were leaked by a low-level military analyst named Daniel Ellsberg.

Fifty years after that 1971 decision, Graham is the subject of a New-York Historical Society exhibition, “Cover Story: Katharine Graham, CEO.” Opening May 21 and running through Oct. 3, “Cover Story” offers an in-depth look at the woman best known for standing up for press freedom and staring down a corrupt president.

It is not the first museum exhibit on Graham — the Smithsonian’s National Portrait Gallery spotlighted her in 2010 as part of its “One Life” series — but “Cover Story” offers a deep examination of her personal and career achievements within the context of a rapidly changing world. The exhibit features almost 200 items, including photographs, ballgowns and a new video interview with Warren Buffett. Through those artifacts, it considers the role of women in media, Graham’s crashing through the business world’s glass ceiling, and her gradual and uneasy embrace of what was then called women’s lib.

Curators Jeanne Gardner Gutierrez and Valerie Paley frame the exhibition around feminist and author Gloria Steinem’s 2001 eulogy of Graham, who died after a fall at 84. “As a transitional woman, with all the pain and late blooming that implies, Katharine Graham helped bring us out of a very different past. Because we are all in transition to an equality no one has ever known, she will be a touchstone for the future,” Steinem said about her friend.

The passage was an “aha moment,” Gutierrez said, and it shapes the exhibition.

Graham “grew up with one set of very gendered expectations. She was raised to be a wife, to raise children and engage in genteel, ladylike activities,” Gutierrez said. “Then in the mid- to late ’60s and ’70s, there is this total revolution, not only in her life and for women in journalism, but for American women as a whole.”

Graham was born in New York City in 1917 and was a teenager when her father, financier Eugene Meyer, bought The Washington Post in 1933. She attended an all-girls boarding school from fifth grade through high school before enrolling at Vassar College. (“It simply was the ‘in’ place at the time,” she recalled in her 1997 Pulitzer Prize-winning memoir, “Personal History.”) She transferred to the University of Chicago after two years and studied American history with the hopes of working in journalism. In 1940, two years after graduation, she married lawyer Philip L. Graham and settled into a traditional life as wife, mother and hostess. She was at her husband’s side when her father passed the company to him in 1946.

His suicide in 1963 changed everything.

“Circumstances put her in a position of power,” Paley said. “It is a story of out of this great despair over her husband’s death comes this remarkable transformation.”

The exhibition does not suggest the transformation was easy. It details her doubts about her abilities, emotions well known to her family and friends, said her son, Donald E. Graham, one of several family members who loaned objects to the curators for their research.

“Most people expected her to sell [The Post] to a newspaper company and several called her about it,” he said. “She had another idea. Somehow, she herself could run it.”

“If she had understood what she was getting into, she might have said no,” he added, recalling that her four children were “cheering loudly” for her to step in. “We thought she could do it.”

Graham’s own words describe the challenges she faced, especially from within the organization.

“I didn’t understand the immensity of what lay before me, how frightened I would be by most of it, how tough it was going to be and how many anxious hours and days I would spend for a long, long time,” she wrote in “Personal History.” “Nor did I realize how much I was eventually going to enjoy it all.”

She was remarkably successful. Under her leadership, The Post became one of the nation’s top newspapers, and the company continued to expand, adding cable television and test preparation businesses to its portfolio. Warren Buffett, an early shareholder, became a mentor and friend. She made history in 1972 as the first woman to run a Fortune 500 company when she was appointed CEO. When she stepped down in 1991, the value of the company’s shares had increased 3,000 percent.

“She answered one question: Can a woman, any woman, run a large business?” Don Graham said. “Warren Buffett said, after Katharine Graham’s career, it wasn’t possible to ask that anymore.”

Central to the exhibit is Truman Capote’s legendary Black and White Ball, a glamorous evening at the Plaza Hotel that the “In Cold Blood” author gave in Graham’s honor. A coming out for the still-unknown publisher, the 1966 ball attracted more than 500 guests from Hollywood, fashion, arts, media and philanthropic circles. The exhibition includes a photograph of a smiling Graham clasping Capote’s hand, with New York Times reporter Charlotte Curtis jotting notes on a pad in the background. Also pictured are Douglas Fairbanks Jr., Frank Sinatra and Mia Farrow, Oscar de la Renta, Rose Kennedy and Gordon Parks. Graham’s beaded Bergdorf Goodman gown and Halston mask will be on view, along with Capote’s tuxedo ­jacket.

Gutierrez and Paley present the ball as crucial to Graham’s evolution because it boosted her self-confidence, raised her national profile and introduced her to many people who became lifelong friends. The ball also showcased Capote’s gift for bringing together influential people from different circles, Gutierrez added.

“She took that principle of bringing different people together socially. She became a famous hostess in Washington, although she didn’t care for that term,” Gutierrez said. “Warren Buffett wrote about Katharine’s parties and how much that helped her consolidate her influence in Washington. She was able to facilitate that, and for a newspaper woman that must have been gold.”

Don Graham did not attend the ball because he was in basic training at Fort Bragg, N.C., but he remembers that it was “a huge deal” for his mother. However, he does not think she needed Capote’s social tutelage.

“She was always good at that. She had a gift for getting people together and a gift for getting people to talk,” he said, recalling a business lunch they had for a small group while he was publisher and she was CEO. Traffic caused her to be a little late, he said, “and we were talking a little awkwardly, a little formally. And then she came in and the conversation became much easier.”

The exhibition uses photographs to document the Pentagon Papers and Watergate, but it focuses more on lesser-known, and often difficult, incidents in her career. The exhibit details her struggles with the 1975 pressman’s strike and landmark employment discrimination lawsuits brought by female and Black employees. It also examines her uneasy acceptance of the feminist movement, a paradox given her trailblazing career.

“Like many privileged women, initially she did not understand what that movement would mean for women writ large,” said Louise Mirrer, the New-York Historical Society’s president and CEO.

Graham chronicled her self-doubt and self-discovery in her book.

“She writes in her memoir that all the time spent being the only woman in the room left her feeling ‘squelched.’ ” Gutierrez said. “That is probably familiar to a lot of us, the feeling of being squelched.”

Graham’s life bridges the past and shows the roots of current struggles for press freedom and workplace equality, Mirrer added.

“Do young women and men today think of her when they think of notable women who made a difference in our lives?” she asked. “We hope this exhibition will do that.”

Cover Story: Katharine Graham, CEO, May 21-Oct. 3, at Joyce B. Cowin Women’s History Gallery of the New-York Historical Society, 170 Central Park West at Richard Gilder Way (77th Street), New York.