He showed an early talent and affection for music and languages.

As a young man he considered a career as a pianist and he spoke French, Italian, Spanish, Russian and Yiddish.

In the crisis years around 1930 he joined Verein Sozialistischer Ärzte (The Association of Socialist Doctors) and co-founded a center for drug addicts.

After World War II he became director of the psychiatric clinic in Erlangen.

In 1947 Leibbrand was appointed to a tenured professorship in the history of medicine at the University of Erlangen.