| 2014-2022 | Professor of Non-State Actors and Transnational Law, Centre for Trust, Peace and Social Relations, Coventry University, UK | |
| 2010- 2014 | Professor in International Relations and Public International Law, Faculty of Social Sciences, Oxford Brookes University, Oxford, UK. |  |
| 2009-2010 | Associate Professor & Academic Director, Institute for International Law of Peace and Armed Conflict, Ruhr-Universität Bochum, Germany. | |
| 2000-2008 | Associate Professor, Department of International Law, Law Faculty, Erasmus University Rotterdam, the Netherlands. | |
| 1998-1999 | Assistant Professor, Department of International Relations, Faculty of Political & Social-Cultural Sciences, University of Amsterdam, the Netherlands. | |
| 1994-1998 | Assistant Professor, Law and Governance Group, Department of Social Sciences, Agricultural University Wageningen, the Netherlands. | |
| 1994-1998 | Project Manager, Romania Project, Milieukontakt Oost-Europa, the Netherlands. | |
| 1989-1994 | PhD Candidate, Department of Public International Law, University of Utrecht, the Netherlands. | |
| 1988-1989 | Junior Lecturer, Department of Public International Law, University of Utrecht, the Netherlands. |