In 1948, he joined the Institute for Advanced Study in Princeton, New Jersey; as Max Jammer wrote much later, "For Rohrlich this was one of the highlights of his life: he met Einstein, Pais, Placzek, Uhlenbeck, Dyson, and the mathematicians Gödel, von Neumann, and Weyl; he was present when von Laue and Yukawa visited the Institute.
There he met Richard Feynman, which revived his interest in the problems of divergences in the classical electrodynamic theory for charged particles, for which he later became a leading expert.
In 1953 he became an associate professor (and colleague of Jauch) at the University of Iowa; the text The theory of Photons and Electrons was first published in 1955.
[7][8] In the 1980s, he put his focus on the philosophy of science, and wrote the text From Paradox to Reality: Our Basic Concepts of the Physical World.
He remained active in research for many years thereafter, and in 2009 was honored by the lifetime "outstanding referee" designation of the American Physical Society.