His academic career began in 1948 with a teaching position at Iowa State College; he served as Assistant Professor of Chemistry. In his capacity there he published his eponymous postulate which is now widely known as the most important publication in the field of organic photochemistry. He moved to the University of Oxford and University of Basel as a Guggenheim Fellow and National Science Foundation Fellow, respectively. In 1958, he moved to the California Institute of Technology as a Professor of Organic Chemistry. Later he was appointed the Arthur Amos Noyes Professor of Chemistry and subsequently went on to lead the Departments of Chemistry and Chemical Engineering. After 14 years teaching and serving as an academic administrator at Caltech he moved in 1972 to the University of California Santa Cruz. At University of California Santa Cruz he served as both a professor and the Chancellor of the natural sciences.