After returning from the war, he finished his doctoral work at the University of Texas and went on to teach mathematics at the University of Pennsylvania, where he went through the ranks of instructor, assistant professor, and associate professor (from 1951–1956). During this time he also spent two years (the academic years 1951–1952 and 1955–1956) at the Institute for Advanced Study in Princeton, New Jersey. He then accepted a post at Louisiana State University, where he became the university's first Boyd Professor of mathematics.