David Gaub McCullough was born in Pittsburgh on July 7, 1933, one of four sons of Ruth (Rankin) and Christian McCullough. If he ever knew a dark day in his early years, there seems to be no record of it. In interviews he spoke of loving the city schools he attended and having a healthy mix of interests, including reading, sports and drawing cartoons, all encouraged by his parents.
In 1951 he went to Yale, where he became a member of Yale’s secretive student society Skull and Bones and was inspired by an English faculty that included Robert Penn Warren, John O’Hara and John Hersey. Lunchtime conversations with the novelist-playwright Thornton Wilder, he later said, especially influenced his approach to choosing subjects — first, be intensely interested in them — and taught him the importance of maintaining “an air of freedom in the story line,” even when writing nonfiction.
Mr. McCullough graduated in 1955 with honors in literature. He had given some thought to writing fiction or plays or, on the other hand, going to medical school; in the event, he signed on as a trainee at Sports Illustrated, which he had begun the previous year. He then came jobs as a writer and editor, first at the United States Information Agency in Washington and then for the history magazine American Heritage.
Working nights and weekends over three years, he completed his first book: “The Johnstown Flood,” published in 1968, established him as one who could take a familiar story — the great dam failure in Pennsylvania in 1889 that killed more than 2,000 people — and give it a larger life. “A superb job,” Alden Whitman of The Times wrote. “Scholarly yet vivid, balanced yet incisive.”
With the success of “The Johnstown Flood” and the support of his wife, he took a leap of faith, quitting his day job to write history and biography full time while the couple raised five children. Throughout his career Mr. McCullough and his wife would read his early drafts aloud to each other — a practice he credited with improving his writing enormously. Ms. McCullough died in June at 89 at the family’s home on Martha’s Vineyard, Mass., where she had grown up. He had met Rosalee Barnes at a dance in Pittsburgh when they were teenagers, and they married in 1954.