MacCormick was a lecturer in jurisprudence at the School of Law, University of Dundee (which was attached to University of St Andrews at that time) from 1965 to 1967. Following this, he was a fellow and tutor in jurisprudence, Balliol College, Oxford 1968–1972, and thereafter held the Regius Chair of Public Law and the Law of Nature and Nations at the University of Edinburgh. He was also Leverhulme Research Professor at Edinburgh from 1997 to 1999, and from 2004 to 2008. In addition, he held the position of Dean of Law Faculty between 1973–76 and was sometime Provost of the Faculty Group of Law and Social Science, and Vice-Principal for International Affairs.