Professor Zimmermann studied Classical Indology, Tibetan Studies, and Japanese Studies at the University of Hamburg, where he received his doctorate for a dissertation on the origins of the doctrine of Buddha-nature in India. He subsequently continued his studies for several years at universities in Kyoto and Tokyo. He later worked on a project for the preservation of Nepalese-German manuscripts, carried out by the German Research Foundation (DFG) in Hamburg and Kathmandu. From 2002 to 2003, he also served as Director of the Nepal Research Center.

After four years as a research associate in the Department of Religious Studies at Stanford University in the United States and as Director of the Stanford Center for Buddhist Studies, he was appointed Professor of Indian Buddhism at the Asia-Africa Institute of the University of Hamburg in 2007.

His research interests encompass Indian Mahāyāna Buddhism in all its forms of expression, with particular emphasis on the textual history of Buddhist traditions preserved in the canonical languages of transmission in India, Tibet, and China. He also works on Buddhist ethics, including the relationship between Buddhism, political power, and violence. His interests further extend to contemporary developments in Buddhism in Asia and the West.