Michael McCabe had a fascinating and varied military career. He claimed membership of Na Fianna Éireann and the Irish Volunteers from 1911. He states that he participated in the Howth Gun running on 26 July 1914. Following his participation in the 1916 Easter Rising McCabe was detained for ten days and released on account of his age. McCabe joined the British Army in 1917 and served until April 1922.
He then joined the (anti-Treaty IRA) Four Courts Garrison, Dublin with which he served as a Sergeant Major and Drill Instructor taking part in arms raids on the Curragh Camp and Dublin Port and Docks/Customs House in 1922. He was captured by National Army forces following the surrender at the Four Courts in July 1922 and interned for the remainder of the Civil War at Mountjoy, Dublin and Newbridge, County Kildare. He was released in December 1923.
McCabe again joined the British Army and served with 2 Battalion, The Gold Coast Regiment, Royal West African Frontier Force in the 1930s and during the Second World War. According to his file he was interviewed before the Advisory Committee on 4 September 1939 (three days after the outbreak of the Second World War) but later returned to Africa. By late 1946 it appears that McCabe had returned to Ireland and was living in Griffith Avenue, Dublin.