Professor, The Johns Hopkins University, 1967-75 (Chairman, English Department, 1968-75; Andrew W. Mellon Professor of the Humanities, 1973-75)
Professor, Yale University, 1975-84 (Thomas E. Donnelley Professor, 1980-84; Director of Graduate Studies, English Department 1976-83; Director, British Studies Program, 1976-84)
Member of Academic and Advisory Committees and Governing Board of the Yale Center for British Art and the Paul Mellon Centre for British Art in London, 1975-84
Professor, The Johns Hopkins University, 1984- (Chairman, English Department, 1985-91; Mayer Professor of the Humanities, 1985-)
Member, editorial board, ELH, (1967-)
Senior Ed., ELH (1985-); Studies in English Literature (1963-); PMLA (1973-76); Eighteenth-Century Studies (1966-74); Johns Hopkins University Press (1973-75; 1985-89)