Arthur M. Schlesinger Jr. ’38—prolific historian, noted Harvard professor, and a prominent “fighting liberal” throughout the 1950s and 60s, suffered a fatal heart attack during dinner with his family on February 28. He was 89.

Schlesinger, a two-time Pulitzer prize winner, author of over two dozen works on American politics and history, and a chief political advisor to John F. Kennedy ’40, moved from one big room to the next, rising from his Thayer dorm to occupy an elite office in the nation’s capitol.

“This is an immense loss for everyone who enjoys reading history,” David Gergen, director of the Center for Public Leadership at the Kennedy School of Government, said.

Born in Columbus, Ohio on March 15, 1917, Schlesinger left the midwest for Cambridge at the age of seven, when his father—Arthur M. Schlesinger Sr., also a leading American historian—joined the faculty at Harvard.

He would spend four years on campus as an undergraduate beginning in the fall of 1934.

The Philips Exeter Academy graduate quickly impressed his peers and professors, earning a spot as a freshman on The Advocate and beating out 612 classmates to win the LeBaron Russell Briggs Prize in history that same year.

The voluminous writer—known for 5,000-word days—kept a journal his sophomore year, which he summed up with five words: “Weather, Work, Smoking, Liquor and Love.” He joined fellow literary types as a member of the Signet Society, praising the Dunster Street club for serving “the best luncheon in Cambridge.”

In a 2000 memoir, Schlesinger wrote that he grew bored by his junior year, only drawn out of his doldrums by his History and Literature thesis on the New England Transcendentalist Orestes A. Brownson.

Schlesinger came back to teach at Harvard in 1947, but his work—and his thoughts—never strayed far from Washington DC. He warned of the dangers posed by Stalinism and counseled Democratic candidates until he joined the John F. Kennedy’s administration as an adviser (his work was expansive and never clearly defined). He won his second Pulitzer Prize—the first had come in 1946 for “The Age of Jackson”—for the biographical “A Thousand Days: John F. Kennedy in The White House.”

Schlesinger’s glowing portrayal of Roosevelt and Kennedy has since been criticized as overly partisan, but Schlesinger’s ever-present closeness will likely be remembered not as a fault, but as the mark of an articulate, scholarly lion of liberal causes.

“His achievements as a writer and as a partisan are undeniable, and he should be remembered as someone who made a lifelong effort to put his talents as a writer to good use in the public sphere,” Kemper Professor of American History James T. Kloppenberg said.

In a statement, President-elect Drew G. Faust described Schlesinger as a “great friend to Harvard.”

“I will miss his sharp intelligence, his delightful wit, and his broad understanding of times past and present,” Faust said of her fellow historian.

Schlesinger is survived by six children—four from his first marriage to Marian Cannon, and two from his second to Alexandra Emmet.