Warren taught at the University of Michigan for twenty years. During this period he was Fellow of the Kenyon School of English during the summers of 1948-1950, a Senior Fellow of Indiana University's School of Letters from 1950 to 1964 and New York University's Berg Visiting Professor of English from 1953 to 1954. In 1951 he was awarded a Guggenheim Fellowship. On September 5, 1959, he married Antonia Degen Keese. Warren retired from the University of Michigan in 1968. He was known for his then-revolutionary abandonment of the formal lecture.