From 1979 to 1995 Kalender worked in the research laboratories of Siemens Medical Systems in Erlangen, Germany ; he was appointed head of the Medical Physics group in 1988. In 1995 he was appointed full professor and chairman of the newly established Institute of Medical Physics at the Friedrich-Alexander-University Erlangen-Nuremberg, Germany. In 1999 he became distinguished visiting professor to the Department of Radiology at Stanford University, Stanford, CA, US.