Mads Andenas holds a Chair in the Faculty of Law, the University of Oslo (from 2008). He served as the Chair-Rapporteur of the UN Working Group on Arbitrary Detention of which he became a member in 2009 (his second and not renewable term expired in 2015).
In 2019 he was appointed an honorary Queen’s Counsel. From the Lord Chancellor's recommendation:
Professor Mads Andenas is considered a stellar academic and has been recommended for his work in the fields of comparative and international law, in familiarising academic and practising lawyers and the judiciary in this jurisdiction with other systems of law and by encouraging exchanges of views and approaches between common and civil lawyers. He has written many books on the subject. He has established a series of annual seminars on pressing issues as seen from European Supreme Courts. This was inaugurated by a seminar in the UK Supreme Court with the participation of a number of leading UK practitioners and judges.
See also https://www.gov.uk/government/news/lord-chancellor-welcomes-promotion-of-new-silks--2
He has held senior academic appointments in the United Kingdom, including as Director of the British Institute of International and Comparative Law, London and Director of the Centre of European Law at King’s College, University of London.
He has held a part-time appointment as a Senior Fellow in European Community Law at the Institute of European and Comparative Law, University of Oxford 2001-2009, held concurrently with a Supernumerary fellowship at Harris Manchester College, Oxford. He was the Director of the Centre of Corporate and Financial Law until 2019 and continues as a Senior Research Fellow of Corporate and Commercial Law at the Institute of Advanced Legal Studies, School of Advanced Study, University of London, with which he has been associated since the early 1990s.
He has been a Visiting Professor at the University of Paris I (Sorbonne) in 2006 and in different periods at the University of Rome La Sapienza from 2002. In 2002–3 he held the Chaire W J Ganshof van der Meersch under the Fondation Philippe Wiener—Maurice Anspach at the Université Libre de Bruxelles. He has been a Herbert Smith Visitor at the University of Cambridge. In 2005 he was a Fellow of Netherlands Institute for Advanced Study in the Humanities and Social Sciences (NIAS). In 2005 he held the Paul Hastings Visiting Professorship at the Faculty of Law at the University of Hong Kong, and he is currently a member of the Advisory Board of the HKU Asian Institute of International Financial Law. In 2006 he delivered the Annual Guido Carli Lecture at the University of LUISS Guido Carli, Rome. He has been a part time professor at the European University Institute, Florence where he participated in a research project on European regulatory private law. In 2016 he was a Visiting Fellow at All Souls College, University of Oxford.
He delivered the Peter Ellinger Annual Lecture at the National University of Singapore in 2020.
He is a member of the Curatorium of the African Institute of International Law which is based in Arusha (www.aiil-iadi.org). He was the Secretary General of the Fédération internationale de droit européen (FIDE) 2000–2002. He served as the Chair-Rapporteur of the UN Working Group on Arbitrary Detention of which he became a member in 2009 (his second and not renewable term expired in 2015).
He has been the General Editor of the International and Comparative Law Quarterly (Oxford University Press, then Cambridge University Press). He is currently the General Editor of European Business Law Review and an Editor of European Public Law (both Kluwer Law International) and on the editorial boards of some ten other law journals and book series, including as member of the Advisory Committee of Peking University Law Journal. He has taken part in the evaluation of law schools and institutes, including of the Dipartimento di diritto comparato at the University of Padua, and in the classification of publications for research funding and appointments, for instance in the Valutazione della Qualità della Ricerca in legal research for the Italian Agenzia Nazionale di Valutazione del Sistema Universitario e della Ricerca (ANVUR) and in chairing the Norwegian National Committee for the classification of legal research publications.
He was the UN Special Rapporteur on Arbitrary Detention, and the Chair of the UN Working Group on Arbitrary Detention which reports to the UN Human Rights Council and the UN General Assembly. He was appointed a UN Human Rights Mandate Holder serving and a member of Working Group in 2009, and was elected chair and Special Rapporteur in 2013. His second three year appointment (which was non-renewable) ran out in 2015.
He is a member of the Executive Council of the International Law Association.
He was the Secretary General of the Fédération internationale de droit européen 2000-2002, the Hon Secretary of the UK Association of European Law 1997-2008 and the Hon Secretary of the UK Committee of Comparative Law 1999-2005. He was the Chair, Association of Human Rights Institutes (AHRI) in 2008, and has been a member of the International Law Association's Securities Law Committee since 1996. He has been the chair of the Norwegian Association of European Law and a member of the board of the Norwegian Association of International Law from 2009.
In 2008, he was appointed by the Institut de France as a member of the committee for the Institut's Prix international Aristotle Onassis pour le Droit. In 2011 he received for his human rights work the Don Pino Puglisi Prize in memory of the priest killed by the mafia in Palermo in 1993 and recently declared a martyr and beatified.
He was the Director of the Legal Office of the Royal Norwegian Ministry of Trade and Shipping 1985-86, and in the Royal Norwegian Ministry of Finance 1986-93, first the Director of the Banking Office, and then an Assistant and finally a Deputy Director General in the Economic Policy Department. He was Legal Adviser in the European Bank for Reconstruction and Development in its first phase of operation, responsible for EBRD's law reform assistance and advice on international law. He has worked as a consultant to the World Bank and to the International Monetary Fund.