Nan Tucker McEvoy at the olive-oil press at McEvoy Ranch in Petaluma, Calif., in 2006. Ms. McEvoy led the parent company of the San Francisco Chronicle. (Eric Risberg/AP)

Nan Tucker McEvoy, a newspaper heiress who headed the parent company of the San Francisco Chronicle in the 1980s and 1990s and who, as a longtime Washington resident, became the first woman to chair the governing board of the Smithsonian American Art Museum, died March 26 at her home in San Francisco. She was 95.

She had complications from a stroke, said her son, Nion McEvoy.

Ms. McEvoy was already one of the richest women in the United States when she netted hundreds of millions of dollars in 1999 from the sale of the Chronicle, which she led for 14 years as board chairwoman and principal owner.

Her grandfather, M.H. de Young, founded the Chronicle with his brother in 1865, and Ms. McEvoy worked as a reporter at the newspaper in her 20s. Since the 1990s, she had presided over the McEvoy Ranch in California, where she became one of the country’s foremost producers of premium olive oil.

Yet for 36 years, Ms. McEvoy made her home in Washington, where she was a quiet but forceful figure in the worlds of politics, public service and cultural philanthropy. She participated in the 1956 presidential campaign of Democratic candidate Adlai Stevenson and, in 1961, became a top aide to R. Sargent Shriver, the founding director of the Peace Corps.

Ms. McEvoy led the Peace Corps’ Africa program for two years before becoming the agency’s head recruiter of permanent staff members. In 1965, she opened the Washington office of the Population Council, a nonprofit agency addressing global issues of population, poverty, development and health. She also served as a U.S. delegate to UNESCO, the cultural arm of the United Nations, in the 1960s.

As a longtime proponent of women’s rights, Ms. McEvoy was a founder of Preterm, an abortion clinic in the District for low-income women. The clinic opened in 1971, two years before the Supreme Court’s Roe v. Wade decision legalizing abortion, and was considered a model for clinics across the country.

In a statement, House Minority Leader Nancy Pelosi (D-Calif.) called Ms. McEvoy “a trailblazing, entrepreneurial woman” who “reminded us of our responsibility to improve our communities and our world.”

A noted art collector, Ms. McEvoy was named to the board of commissioners of what is now the Smithsonian American Art Museum in 1979. Three years later, she became the first woman to chair the board.

In a one-sentence memorandum, Ms. McEvoy pledged $10 million to the museum to build a “first-class auditorium with all the bells and whistles.” The 346-seat Nan Tucker McEvoy auditorium opened in 2006 and serves both the American Art Museum and the National Portrait Gallery, which share the same building.

“She was a wonderful leader who led by example, in a quiet way,” Elizabeth Broun, director of the Smithsonian American Art Museum, said in an interview. “She was extremely capable, and she knew what she wanted.”

In 1981, Ms. McEvoy became chairwoman of the parent company of the Chronicle, which was still controlled by her family. She moved from Washington to San Francisco in 1989 to manage the media business, which included the newspaper, a book publishing company, television stations and other holdings. She and her son owned one-third of the company; the other shares were held by about two dozen other family members.

Ms. McEvoy was often described as a West Coast version of former Washington Post Co. chairman Katharine Graham, her longtime friend and Georgetown neighbor.

In San Francisco, Ms. McEvoy replaced several relatives at the underperforming Chronicle. She especially disliked the paper’s conservative editorial slant under the direction of its publisher, Richard T. Thieriot, who was Ms. McEvoy’s cousin.

“It made me mad, in a city that is not conservative Republican,” she told the New York Times in 1994, that “we did not reflect the sense of the city or the way I felt about things.”

Despite improvements to the Chronicle’s journalism and bottom line, Ms. McEvoy’s moves led to a rift in the family. When some suggested that the company should be sold, she reportedly thundered, “Over my dead body!”

Tensions boiled over on April 19, 1995, when a group of shareholders — all of them relatives of Ms. McEvoy — passed a bylaw requiring members of the board to retire at 73. Ms. McEvoy, then 75, was the only person affected. She was immediately forced out of her job as head of the company.

Members of the Chronicle staff signed a petition in support of Ms. McEvoy. She filed a lawsuit against 18 of her relatives, but it was dismissed. In 1999, the Chronicle was sold for $660 million to Hearst, the parent company of the San Francisco Examiner, the Chronicle’s longtime rival.

“Families are very complicated,” Ms. McEvoy told the San Jose Mercury News in 2001. “That’s as much of an answer as I can give you.”

Phyllis Ann Tucker was born July 15, 1919, in San Mateo, Calif. Because her mother was also named Phyllis, she went by her middle name, which soon became “Nan.”

Her father, Nion Tucker, won an Olympic gold medal in bobsledding in 1928 and was a business executive who helped form United Airlines. Her only sibling, a brother, was killed in the Battle of Iwo Jima during World War II.

Ms. McEvoy attended Catholic convent schools in California and Europe. In her 20s, she wanted to become a reporter at the Chronicle but was told the paper didn’t hire women. She staged a sit-down strike at the office of the editor — her uncle — until she was given a job.

In 1945, she covered discussions in San Francisco concerning the creation of the United Nations and scored an exclusive scoop when she obtained a copy of the U.N. charter before it was released.

She later worked at the New York Herald Tribune and on the business side of The Washington Post before she was married in 1948 to Dennis McEvoy. They moved to Japan, where her husband was in charge of Asian operations for Reader’s Digest.

Ms. McEvoy settled in Washington in 1953 and, after a divorce, raised her son by herself. She never remarried.

Survivors include her son, Nion McEvoy, chief executive of Chronicle Books, an independent publishing company, of San Francisco; and three grandchildren.

Ms. McEvoy served on the boards of several cultural and educational institutions in California and was an emeritus board member of the Smithsonian American Art Museum until her death. Last year, Forbes magazine estimated the net worth of Ms. McEvoy and her son at $770 million.

In the late 1980s, Ms. McEvoy bought a 550-acre farm in Marin County, Calif., as a country retreat. The property was zoned for agriculture, and she considered raising cattle — “They are always having stomach aches or getting foot aches,” she said — or planting grapes for wine. She rejected both ideas in favor of olive groves.

“Everyone told me it would never work,” she told Marin magazine in 2007, “so we brought an expert out from Tuscany to assess the ranch, and luckily, Marin County’s soil and microclimate are perfect for growing Tuscan olives.”

More than 18,000 olive trees now grow on the hillsides of McEvoy Ranch. Olive oil from the ranch has received top awards from food magazines and is widely sold in specialty stores.

“It is really wonderful to start something no one else is doing,” she told the Mercury News in 2001.

“If you have some personality, it helps,” she added. “After all, I came out of the press.”

An earlier version of this obituary incorrectly reported that Adlai Stevenson, the 1956 Democratic candidate for president, was a senator from Illinois. He was a governor.