Mark MacGuigan, son of a former P.E.I. attorney general and supreme court judge, was educated at St. Dunstan's (P.E.I.), University of Toronto, Osgoode Hall Law School and Columbia University. He holds two earned doctorates and four honorary ones. From 196 to 1968, he held various teaching positions, culminating at the University of Windsor, where he was founding dean of the Faculty of Law. He was first elected to the House of Commons in 1968, and re-elected in 1972, 1974, 1979 and 198. He was appointed secretary of state for external affairs in 1982, and judge of the Federal Court of Appeal in 1984.