 Starting 1998, he worked as a postdoctoral fellow for mathematical statistical physics at Rutgers University in New Jersey and then, from 1999 to 2001, on computational biology at the Rockefeller University in New York City where he became a research professor in 2002.In 2003, he became an assistant professor at New York University (tenure track, Department of Biology and Courant Institute for Mathematical Sciences).In 2006, Rajewsky returned to Germany where he became a full professor at the Max-Delbrück-Center for Molecular Medicine (MDC) in Berlin-Buch and at the Charité – Universitätsmedizin Berlin.