He was also for some time a member of the European Commission of Human Rights and a civil servant at the Netherlands ministry of Foreign Affairs.

[6] His thesis, titled De gespecialiseerde organisaties: Hun bouw en inrichting (The Specialized Organizations: Their Structure and Organization), which he defended on 9 October 1957, suggested merging the United Nations and its specialized agencies, comparing the agencies' position to that of the Vatican between 1870 and 1929 (an international legal person, but lacking some aspects).

[8] In 1963 Schermers was appointed lector (roughly equivalent to reader) in the law of international organizations and the European Communities at the University of Amsterdam at the suggestion of Arnold Tammes.

[9][1] Two years later he was promoted to full professor in the law of international organizations, the second chair in the field in the Netherlands (the first having been created in Leiden for Ivo Samkalden).

He also was a member of the (provisional) High Council of the European University Institute and a substitute judge of the Amsterdam Court of Appeal for several years.

[15] Amongst his notable books International Institutional Law and Judicial Remedies in the European Union are classics and have run into numerous editions.

He became Director of the Europa Instituut at the University of Leiden and Executive Editor of the Common Market Law Review, the leading English-language journal in its field.

Schermers was a scholar of genuine intellectual independence: at the time when all leading Dutch international law scholars without exception signed a document urging sanctions against South Africa and suggested that they were indeed required under public international law, he was the lone dissenter (on purely technical grounds) and in a highly controversial move, made his views public.