Professor Kjems studied at Aarhus University, where he completed his PhD in Biostructural Chemistry in 1989 at the Department of Chemistry. He subsequently spent three years as a postdoctoral fellow at Harvard and the Massachusetts Institute of Technology (MIT) in Cambridge, USA, prior to returning to Aarhus. He was appointed associate professor at the Department of Molecular Biology and Genetics in 1994 and professor in 2003. With a main field of research in nanomedicine, Professor Kjems has over the years contributed with world-class research in this area, and he has built up a large international network. 

From 2015 to 2017, Jørgen Kjems was head of department at the Interdisciplinary Nanoscience Center (iNANO) at Aarhus University and in 2018 he became the head of the Centre for Cellular signalling Patterns (CellPAT), a collaborative research network supported by the Danish National Research Foundation.