On 11 April 1981, Black was commissioned into the Welsh Guards as a second lieutenant. He commanded a platoon in the Falklands War of 1982, surviving the bombing of RFA Sir Galahad,Nick van der Bijl, 5th Infantry Brigade in the Falklands 1982 (2003), p. 135 and was promoted lieutenant on 25 January 1984, captain on 11 October 1987, and major on 30 September 1991. He had three tours of Northern Ireland, where one of his roles was as an intelligence officer in Republican West Belfast, and he also served with the British Army of the Rhine and the United Nations Peacekeeping Force in Cyprus. After attending the Staff College, Black specialised in intelligence. In the 1997 New Year Honours, he was appointed Member of the Order of the British Empire for his Defence Intelligence Staff work in connection with the break-up of Yugoslavia.
