A disciple of Egon Brunswick and Charlotte and Karl Bühler, he became the president of the Academic Association for Medical Schools and displayed a considerable interest in the applications of psychology.
In this context, he enjoyed contacts with psychoanalysts including Alfred Adler and psychotherapists such as Viktor Frankl.
Beginning in 1959, he held the Lehrstuhl für Psychologie and served as department chair at the University of Hamburg, from which he retired in 1979.
Publishing in 1957 the widely read Fischer-Lexikon Psychologie, as well as Gruppendynamik he was instrumental in "Americanizing" the field which as a consequence became much more empirically oriented.
At the same time his activities as a columnist for the newspaper Hamburger Abendblatt and the weekly magazine Die Zeit made him nationally prominent but also involved him in a bitter controversy when he argued in favor of a general amnesty for German war criminals.