His biography The Rise of Theodore Roosevelt won the Pulitzer Prize and National Book Award in 1980. After spending 14 years as President Reagan's authorized biographer, he published the national bestseller Dutch: A Memoir of Ronald Reagan in 1999 (edited by Robert Loomis, executive editor at Random House, Morris' publisher). This book generated controversy because, although Morris had access to Reagan's papers and correspondence, including his private diary, and he had been chosen as Reagan's official biographer, Morris wrote the book in a fiction-like fashion with a fictional version of himself as the narrator. Morris chose this course because, he admitted, he was never able to bring the president into focus. "He was truly one of the strangest men who’s ever lived," Morris said. "Nobody around him understood him. I, every person I interviewed, almost without exception, eventually would say, 'You know, I could never really figure him out.'
Morris's other books include Theodore Rex (2001), the second in a projected three-volume chronicle of the life of Theodore Roosevelt, and Beethoven: The Universal Composer (2005). Mr. Morris has also written extensively on travel and the arts for such publications as The New Yorker, the New York Times, and Harper's Magazine.