 At the age of 53, Greenwell married Sibyl Enid Vera Munro Morrison, a divorcee who was the first female practising barrister in New South Wales, at St Stephen's Presbyterian Church on 16 March 1937.Greenwell served as an Army Officer in both World War I and World War II.Greenwell died at Collaroy, New South Wales, on 7 February 1961.