Who was the first Black woman to join the board of a large U.S. public company?

Until recently, a quick Google search would have directed you to Dolores Wharton, a prominent foundation executive who was married to the late Clifton Wharton Jr., former Rockefeller Foundation chair, CEO of TIAA, and university president.

But that information turned out to be incorrect, according to findings unearthed two years ago by Black Women on Boards (BWOB), a networking and board training organization. The first Black woman on a Fortune 500 board, one member discovered, was actually Patricia Roberts Harris, the late American lawyer, cabinet secretary, and diplomat, who was elected to the board of IBM in 1971. (Wharton had joined the boards of Kellogg and Phillips Petroleum in 1976.)

Now Harris’s feat—breaking into the apex of corporate power once reserved for white men—is not only recognized by the world’s search engine, it’s also celebrated in OnBoard, a new documentary about Harris and the women who have followed suit, often as the first or only Black woman in the boardroom.

Merline Saintil, cofounder of BWOB and co–executive producer and coproducer of OnBoard, says the film is part of a wider mission to normalize Black women’s corporate success and show fellow Black executives that there’s a pathway to the boardroom because someone went first.

Patricia Roberts Harris, that someone, was repeatedly first throughout her career.

When she died in 1985, obituaries outlined the remarkable trajectory of her life. She was born into a working-class family in Illinois; attended Howard University on a scholarship, graduating summa cum laude; and worked her way into D.C.’s inner circle. Friends and colleagues described her to the New York Times as a lawyer with a “steel-trap mind” and a self-assured leader with a certain “duality” about her—at once tough, sharp, and charming.

Harris graduated from the George Washington University Law School, first in her class, in 1960. By the time she got the call from IBM, she had been a corporate lawyer, the dean of Howard University School of Law, an organizer for the Democratic Party, cochair of the National Women’s Committee for Civil Rights, and the first Black woman to become an ambassador (to Luxembourg). IBM was not her only board; she later served on those of Scott Paper and Chase Manhattan Bank.

Harris left her IBM directorship in 1977 when she was invited to the U.S. cabinet, serving as secretary of Housing and Urban Development and later as secretary of Health, Education, and Welfare, during the Carter administration.

Before her HUD appointment, she sat for a Senate committee hearing, which produced an exchange that became a part of her legacy. When a lawmaker suggested that Harris, by then among D.C.’s elite, may not be “of the people,” she responded forcefully.

“Senator, to say that I’m not by, and for, and of the people is to show a misunderstanding of who I am and where I came from,” said Harris. “If my life has any meaning at all, it is that those who start as outcasts may end up being part of the system.”

That clip helps to anchor and fuel OnBoard, which debuted at New York City’s Tribeca Festival this week. In 45 minutes, it deftly threads together Harris’s story with that of BWOB, which was launched almost accidentally three years ago by two friends: Saintil, a former Silicon Valley CTO and COO who now sits on the boards of Rocket Lab, GitLab, and three other companies, and Robin Washington, Gilead Sciences’ former CFO, and a director at Salesforce, Alphabet, and Honeywell.

In 2020, they found themselves talking about the surge in requests for Black board members following George Floyd’s murder, as major American firms pledged to fix their company’s race record and diversify their boards. (Although gender diversity has improved over the past few decades, white women—now holding about one-third of board seats—have benefited most. That summer, Black women held only 3% of all Fortune 500 board seats, and 4% of S&P 500 directorships.)

Eager to improve, boards did what boards do: They looked inward, finding Black directors at other companies who might be recruitable. Saintil and Washington were flooded with requests but declined. They had hit capacity. “The way it works, if you’re on board, you’re getting the calls. If you’re not on board, you’re not getting the calls,” says Saintil. “We thought, ‘Hey, we know amazing Black women who just aren’t getting the calls. Can we do something about that?’”

Soon after, the pair organized a Zoom call with 18 Black women executives, which organically evolved into a formal venture. Today, BWOB has more than 200 members globally and more than 30 women placed on public company boards.

Shannon Nash, CFO of Wing, a drone delivery company and Alphabet subsidiary, was among the boxed faces at that Zoom gathering. Her idea was to hire Atlanta-based film director Deborah Riley Draper, whose documentaries bring light to Black history, and make a short film about BWOB’s mission. The multi-hyphenate executive—lawyer, CPA, film producer, and board member at SoFi bank and two other firms—shared her proposal with Saintil and Draper in the fall of 2021, during a short trip that began as a vacation.

At the impromptu offsite, the women searched Google for the first Black woman on a board and were led to Wharton. But just two weeks later, Nash learned from Barry Lawson Williams—the retired founder of investment and consulting firm Williams Pacific Ventures, who has served on more than 18 public boards—that Harris was the real trailblazer. He knew because his mother had idolized Harris and followed every move in her career.

The revelation gave the women further resolve: They needed to correct the neglected history of Black women in corporate governance. Nash would be the documentary’s co-executive producer and producer. “We often don’t include, or center, Black women in the story of big business and corporate boardrooms and capitalism, and the interesting thing about that is Black women have been an important part of the American economy since there’s been an American economy,” says Draper, the film’s director.

Shannon Nash, CFO of Wing and OnBoard coproducer, Deborah Riley Drapper, film director, Merline Saintil, cofounder of Black Women on Boards, and Mikki Taylor, editor-at-large, Essence, at the Onboard debut.

Though the documentary doesn’t dive into Harris’s experiences in corporate boardrooms, it offers a broader history of board diversity, honoring 50 of the women who followed Harris in the ’70s, ’80s, until today, and interviewing Black women directors at companies like Zillow, Symbotic, and Williams-Sonoma.

Taking this long view helps to put the current climate—with its anti-woke boycotts—in perspective. The movement to diversify boards won’t be reversed, says Saintil. A just-published board snapshot from Deloitte shows a sharp increase in Black directors, who now hold 12% of Fortune 500 board seats, with Black women seeing the largest increase (a 47% jump) in new placements since 2020. “It may not continue at the pace it has been in the last few years, post–George Floyd, but the idea that we would turn back and not continue to think of diversity as an advantage and criteria by which we look at things is not possible,” says Saintil. Companies are aware that boardroom diversity leads to stronger performance and better decisions, and groups like BWOB are debunking the myth that there aren’t enough Black executives with the right experience to be directors.

In the past, the barriers that kept Black women out of the CFO and CEO positions played into the absence of Black female directors since boards have traditionally been composed of only executives who have held those roles. Today, says Saintil, more Black executives hold such titles, and boards are tapping directors with varied professional backgrounds. “Now you get your technologists, product people, chief marketing people, CHROs, and a wider group of C-suite executives,” she notes. But Black women still lack the social capital required to join boards. They need introductions, robust networks, golf games with CEOs (which BWOB has arranged), and ongoing support once they become a board member, says Saintil.

Like Harris, who was “not in the self-promotion business” according to her contemporaries, Saintil admits that she doesn’t love the limelight of her new role. At first, she recoiled at the thought of making a documentary—dealing with the hair, the makeup, the press appearances—until she considered the impact the film could have. “I know we will inspire people to think more broadly, that they could reach this trajectory. We will educate people on what boards do,” she says, “We will get people fired up and inspired.”

This story was originally featured on Fortune.com

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