He was the associate editor in the Humanities and History at the University of Chicago Press (1951–53).
At Harvard, he was the executive secretary to the Committee on General Education (1959–1961) and senior tutor at Eliot House (1961–62).
He was professor of History at Washington University in St. Louis (1962–68), professor of History at Brown University (1968–71) and the University of Chicago (1970–1996) where he held the Norman and Edna Freehling Chair in History and the Social Sciences.
At the University of Chicago he chaired the Faculty Committee of the Benton Program for Fellowships in Broadcast Journalism in Broadcast Journalism (1982–86) and the Committee to Plan the University's Centennial.
From 1982 to 1988, he served as special advisor to President Hanna Gray.