Racked by insecurity, she once said that, in taking over the newspaper, she felt pure "terror."
But as the new president of the Post Co., she proved anything but a placeholder. She became a tough, principled and progressive leader and sought out the best journalistic talents of her times.
In 1965, believing the paper needed to be enlivened, she hired Mr. Bradlee, Newsweek's Washington bureau chief, who had been aggressively pursuing the job of Post managing editor.
"Part of me thought, 'What gall this guy has to be so pushy when he doesn't even have the job,'" she wrote. "But part of me thought, 'Maybe this is exactly what we need and what I'm looking for.'"
Mr. Bradlee went on to lead the editorial side of the newspaper as executive editor during its heyday in the 1970s.
In 1971, The New York Times obtained the Pentagon Papers, the government documents concerning the Vietnam War that Daniel Ellsberg, a former Defense Department official, had secretly leaked. A federal judge issued a restraining order against the Times. When the Post obtained its own copy of the documents, it was up to Mrs. Graham to decide whether to defy the court order and publish, as the newsroom recommended, or, as the lawyers advised, not publish.
"Frightened and tense, I took a big gulp and said, 'Go ahead, go ahead, go ahead. Let's go, let's publish,'" Mrs. Graham wrote.
In the end, the restraining order was lifted and the episode became a landmark First Amendment ruling by the Supreme Court.
For the news media and its advocates, the decisions by the Times and Post to publish the Pentagon Papers came to be seen as acts of courage on behalf of a free press.
Soon after, in June 1972, two young Post reporters, Bob Woodward and Carl Bernstein, started investigating a burglary at the Democratic Party headquarters at the Watergate complex.
The administration challenged license renewals for TV stations the Post owned. And for many months even some of Mrs. Graham's friends - and readers - doubted the central premise of the Watergate story: that a president and numerous close allies had taken part in a vast coverup as part of a pattern of crimes aimed at their perceived enemies.
"The credibility of the paper was on the line," Mr. Bernstein told CNN yesterday. "And she had the courage to go with two 28-year-old kids that she really didn't know."
The Post won a Pulitzer Prize for its Watergate coverage in 1973. The next summer, Mr. Nixon resigned.
Watergate catapulted the Post, and Mrs. Graham, to journalistic heights. At the same time, she was successfully tending the business side of the newspaper, turning the Post Co. into a profitable conglomerate of newspaper, magazine, broadcast and cable properties.
She raised money for expansion by taking the company public in 1971. And demonstrating her resolve as a businesswoman, she took on - and broke - the pressmen's union and several other labor units in 1975 after a violent five-month strike.
By the time she turned the mantle of president and CEO of the Post Co. over to her son Donald in 1991, it ranked 271st on the Fortune 500 list and was valued at nearly $2 billion. In 1993, Donald Graham succeeded his mother as company chairman, with Mrs. Graham becoming chairman of the company's executive committee.
Mrs. Graham, who spent Augusts at her home on Martha's Vineyard, had been working on a book about the history of Washington and still came to her office at the Post every day when in town.
Besides her son Donald, Mrs. Graham is survived by her daughter, Elizabeth Weymouth, a Post and Newsweek journalist, of New York; and her two other sons, William Graham, an investor, of Los Angeles; and Stephen Graham, a producer, philanthropist and doctoral student of English literature, of New York; 10 grandchildren and one great-grandchild; and her sister, Ruth M. Epstein of Bronxville, N.Y.
The funeral service will be at 11 a.m. Monday at the National Cathedral in Washington.