John Clarke MacDermott, Baron MacDermott, MC PC (NI) (12 April 1896 – 13 July 1979) was a Northern Irish politician and lawyer who was Lord Chief Justice of Northern Ireland from 1951 to 1971.
Born in 1896, MacDermott was educated at Campbell College, Belfast, and the Queen's University of Belfast. After serving with the Machine Guns Corps in France, Belgium and Germany during the First World War, for which he was awarded the Military Cross and reached the rank of Lieutenant, MacDermott was called to the Irish bar in 1921. Eight years later he was appointed to determine industrial assurance disputes in Northern Ireland, and in 1931 he became a lecturer in Jurisprudence at Queen's University, teaching for four years. In 1936 he was made a King's Counsel, and two years later he was elected to the Northern Ireland House of Commons as an Ulster Unionist member for Queen's University.
In 1940 MacDermott was appointed Minister of Public Security in the Northern Ireland Government, and the following year became the Province's Attorney General. He was succeeded in this post by William Lowry, whose son, Lord Lowry, would eventually succeed MacDermott as Lord Chief Justice. In 1944 he resigned his parliamentary seat on appointment as a High Court Judge for Northern Ireland, and three years later was made a Lord of Appeal in Ordinary, effectively becoming a life peer as Baron MacDermott, of Belmont in the City of Belfast. Lord MacDermott returned from the House of Lords to take up his appointment as Lord Chief Justice of Northern Ireland; his successors to the latter office have become Law Lords subsequently. Whilst LCJ he was affectionately known as "the baron."