In 1941 Jensen was named extraordinarius professor of theoretical physics at the "Technische Hochschule Hannover" (today, the Leibniz University Hannover), and in 1946 became an ordinarius professor there. In 1949 he was appointed ordinarius professor at the Ruprecht Karl University of Heidelberg; and, from 1969 on, was emeritus praecox. He was a guest professor at the University of Wisconsin–Madison (1951), the Institute for Advanced Study (1952), University of California, Berkeley (1952), Indiana University (1953), California Institute of Technology (1953), University of Minnesota, Twin Cities (1956), and University of California, San Diego (1961).