After studying psychology in Landau, Johannes Zimmermann received his doctorate in Heidelberg in 2011 with a dissertation on "Depression and dysfunctional relationship experience". He then worked as a post-doctoral researcher at the University of Kassel in the fields of clinical psychology and psychotherapy as well as psychological diagnostics. In 2015, he accepted a professorship for methodology and psychological diagnostics at the Berlin School of Psychology.

Zimmermann has headed the Department of Differential Psychology in Kassel since September 2018. His research is located at the interface between basic personality psychology and application-oriented clinical diagnostics. For example, he deals with the questions of how problematic personality traits can be optimally systematized and recorded and how diagnostic information can be used profitably for psychological practice.