From 1990 to 2001 he worked at the Institute for Social Research in Frankfurt. 1992 at the Faculty of Social Sciences at Goethe University. Habilitation in Political Science and Political Sociology. 2007 awarded the title of Associate Professor at Goethe University.

Numerous substitute and visiting professorships as well as lectureships in Germany and abroad. From 2007-2012 visiting professor of political science with a focus on political theory at TU Berlin; in winter semester 2012/13 visiting professor of critical social research at JLU Gießen; summer semester 2013 and winter semester 2013/14 visiting professor of critical social theory at Department of Social Sciences at Goethe University Frankfurt. From April 2014 to November 2017 as Senior Fellow at the Rosa Luxemburg Foundation, Berlin.

Lecturer of the Rosa Luxemburg Foundation and the Hans Böckler Foundation, member of the Advisory Board of the Federation of Democratic Scientists and the Scientific Advisory Board of Attac Germany, Chairman of the Scientific Advisory Board of the Rosa Luxemburg Foundation, member of the editorial board of the journal LuXemburg, member of the Scientific Advisory Board of the journal Das Argument, member of the Editorial Advisory Board of the British journal Historical Materialism as well as co-editor of the Turkish journal Felsefelogos.