MacCormick was born in Glasgow on 27 May 1941, the son of one of the SNP's founders, John MacCormick. He was educated at the High School of Glasgow. He graduated MA in Philosophy and English Literature at the University of Glasgow, before benefiting from a Snell Exhibition and taking the BA in Jurisprudence at Balliol College, Oxford. At Oxford, MacCormick came under the influence of Professor H. L. A. Hart, and developed an interest in legal philosophy. In 1982 he was awarded the research degree of LLD by the University of Edinburgh.