Historian, presidential speechwriter, and Pulitzer Prize-winning author of books on the presidencies of Andrew Jackson, Harry Truman, Franklin D. Roosevelt, and John F. Kennedy. His most famous works include The Age of Jackson (1945), The Vital Center: The Politics of Freedom (1949), and A Thousand Days: John F. Kennedy in the White House (1965).
He graduated summa cum laude from Harvard College in 1938. From 1943-45, he served in a spy ring managed by the Office of Strategic Services, a precursor to the CIA.
He worked as a special assistant and speechwriter to President John F. Kennedy, and he was later a major supporter of Robert Kennedy's ill-fated presidential campaign.
With his first wife, Marian Cannon, he had four children. Following his 1970 divorce from Cannon, he wed Alexandra Emmet Allan, with whom he had another child.
During the presidential administration of Harry S. Truman, Schlesinger was one of several founders of a prominent group called Americans for Democratic Action.