Following the completion of his law studies in Oxford, MacCormick took up his first job in Dundee (1965–67), lecturing in both English law and in jurisprudence, with a particular focus on legal reasoning. This chapter first briefly discusses his time in Dundee, before turning to focus mainly on MacCormick’s complex relationship with HLA Hart. Hart, the English-speaking world’s leading legal philosopher of his generation, was in Oxford at the time MacCormick was there – first teaching MacCormick (with lectures on rights and Kelsen), and later being his senior colleague. This chapter focuses on the second period, from 1967 to 1972, during which MacCormick got to know Hart via the debates over student discipline and university authority (both proctorial and academic). Hart wrote a famous report – known as the Hart Report (1969) – in those years, with which MacCormick was very familiar, especially as he then held numerous disciplinary positions in his College. This chapter discusses MacCormick’s readings of Hart (especially his 1981 book on him) in the context of the debates over authority in the University of Oxford in this period, and in the context of MacCormick’s broader interests in moral and political issues.