After receiving his PhD in 2007, he switched fields by joining the laboratory of Dr. Danny Reinberg at NYU School of Medicine, where he worked on the mechanisms of gene repression by Polycomb group proteins and nucleosomal asymmetry between 2008-2014. In late 2014, Philipp joined the Wellcome Trust Centre for Cell Biology at the University of Edinburgh as a Wellcome Trust Sir Henry Dale career development Fellow.
Work in his lab focuses on understanding how the Polycomb and Trithorax systems of histone modifiers interact to regulate gene expression in stem cells, especially in the context of bivalent domains.