 From 1931 to 1933, he had a lectureship in the physics department at the "Eidgenössische Technische Hochschule Zürich".In 1934, he replaced Wolfgang Gaede as director of the physics department at the "Technische Hochschule Karlsruhe" (today, the "Universität Karlsruhe"); Gaede had been forced out by the National Socialist regime as “politically unreliable” after he accepted the Duddell Medal of the London Physical Society in 1933.In 1936, Bühl was an untenured "ausserordentlicher Professor" and from 1937 to 1945 an "ordentlicher Professor" at the "Technische Hochschule Karlsruhe".