- Born 1973 in Tübingen/Germany.
- 1994-9: Studies of Law in Regensburg, Paris X and at Humboldt-University, Berlin.
- 2000 & 2001-5: Research Assistant at the Walter-Hallstein-Institute for European Constitutional Law at Humboldt-University.
- 2000-1: Masters of Law at King's College, London.
- 2003: Doctorate on ‘Ungleichzeitigkeit und Europäisches Verfassungsrecht’ (Supranational Differentiation and European Constitutional Law) at Humboldt-University (honoured with the 'Humboldt-Price').
- 2003: Emile Noël-Price of the European Law Journal for the article ‘Reforming Europe's Common Foreign and Security Policy.’
- 2002-4: Postgraduate Judicial Service Traineeship (Referendariat) at the High Court of Berlin, the Federal Ministry of Justice (European Law Department) and the German Permanent Representation of the EU (Political Department).
- 2005/6: Visiting Fellow at the British Institute of International and Comparative Law.
- 2005-9: Academic co-ordinator of the Graduate Programme ‘Constitutionalism Beyond the State: European Experiences and Global Perspectives’ and Assistant Professor at Humboldt-University.
- 2009: Habilitation at the Faculty of Law of Humboldt-University with a book on 'Migrationsverwaltungsrecht' (Migration Governance through Administrative Law).
- 2012-19: Principal Investigator of the National Centre of Excellence "Cultural Foundations of Social Integration".
- 2016-22: Vice Chairperson of the German Expert Council on Integration and Migration(member since 2016, vice-chair since 2019).
- Chair of Public, European and International Law (formerly held by Kay Hailbronner) at the University of Konstanz (since 2010).
- Co-Director of the Research Centre Immigration & Asylum Law (since 2011).
- Spokesperson of the University of Konstanz in the Research Institute Social Cohesion (RISC) (since 2020).
Migration Law at the German, European and International Level:
- Immigration, asylum, border controls;
- Citizenship, social integration, nationality;
- Domestic and supranational policy debates.
European Constitutional Law:
- Human rights in Europe (Charter, ECHR, national constitutions);
- Foreign Affairs.
- Principal Investigator (PI) of the Cluster of Excellence 'Cultural Foundations of Social Integration' (2012-19)
- Vice-Chairperson of the German Expert Council on Integration and Migration
(2019–22, member since 2016)
- German Member of the Odysseus Network for Legal Experts on Immigration and Asylum in Europe (since 2011)
- Member of the Editorial Board of the "Zeitschrift für Ausländerrecht und Ausländerpolitik" (since 2012)
- Chairperson of the Advisory Committee on the Research Migration at the (German) Federal Office for Migration and Refugees (since 2016, chairman since 2019)
- Expert Partner of the Federal Office for Migration and Refugees, the German member of the European Migration Network EMN (since 2011)