Was associated with the Molengraaff Institute for Private Law, part of the Department of Law (Faculty of Law, Economics, Management and Organization [REBO]), since 1987 working as a full professor in the field of private law, in particular civil law and intellectual property law, more specifically copyright law.
Was guest lecturer a.o. at Wayne State University Law School, Detroit (USA); Berkely Centre for Law and Technology, Berkely (USA); Institute of Intellectual Property, Tokyo (Japan); Stockholm University, Sweden; Washington University School of Law (USA); Fordham University (USA); University of South Africa, Pretoria (S-A); Stellenbosch University (Z-A); University of Chinese Academy of Social Sciences, Beijing (Ch).

Was established as a practising lawyer in Amsterdam with Hocker Advocaten, Van Doorne Advocaten, and VersteegWigmanSprey Advocaten.