Michael Mackey was Irish by birth, the son of Wilma and Peter Mackey, a policeman, from Lavan, County Wicklow, Ireland. At the date of his enlistment in the Australian Army Medical Corps on 10 September 1914 he was living in Perth, Western Australia.Two of his siblings were also in Australia, his brother, Denis, also in Western Australia, and his sister Ellen, his only link with East Melbourne. He named her as his next of kin, living first at 'Gibbs' (Gipps) St. East Melbourne, then at 87 Grey St.

Michael Mackey was 39 years and 6 months old when he enlisted. He embarked at Fremantle on 4 December, 1914, on board H.M.A.T Kyarra A55 and from there went on to Egypt. His record is silent about the next year. His grandson believed that he had fought at Gallipoli with the Light Horse, then serving with the infantry, but this seems unlikely. More probably, as a hospital attendant, he was either on a hospital ship awaiting the injured or with the No. 2 Australian Stationary Hospital, originally located at Mena Camp, Egypt, then moved the day before the Anzac landing to West Mudros on the island of Lemnos. The Medical Camp had to be established from the beginning, in rows of tents on unmade roads. By 13 August it was treating 763 patients, and by September/October the No.2 Australian Stationary Hospital occupied sixty large Marquee tents and had 1,200 beds. When the Gallipoli campaign was over the No.2 A.S.H. transferred to Mudros evacuating the Lemnos camp on 20 January 1916 and arriving at Alexandria on 23 January and then to Tel-el-Kebir in the Suez Canal zone. 

During his time with the Gallipoli campaign Michael Mackey had had two bouts of illness. He had been admitted to Hospital in August 1915 suffering from Pyrexia of unknown origin. In October he was again in hospital, this time for ten days with 'cramps in the stomach'. Michael Mackey's record shows him as transferring with the 2nd A.S.H. to Alexandria, and on to Tel-el-Kebir, before being 'invalided back to base'. In May 1916 he was admitted with 'cholecystitits' (inflammation of the gall bladder). He had another week in hospital at the end of December 1916, with an undiagnosed condition, and in June 1917 was admitted to the 14th Australian General Hospital at Tel-el- Kebir with 'debility' and in August with diarrhoea.

On 21 October 1917 he was back at the No.2 Australia Stationary Hospital and struck off strength. He was given furlough and, rather than returning to Australia, was to go to England. The medical authorities in Egypt may have known he would not survive a long journey. He embarked on 14 October, 1917, on board H.T. Nile from Alexandria, but must have been too ill to complete the journey. The ship may well have called in at Marseilles and transferred Mackey directly to hospital

Michael Mackey died on 9 November 1917 at the No. 2 Military Hospital Rest Camp, St Germain au Mont D'Or, near Lyon. His record said he died from myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the membranous bag surrounding the heart), probably resulting from amoebic hepatitis. Streptococcal infection was common in camp and diptheric myocarditis had a particualrly poor prognosis. His age, forty-two, may also have been against him.

Michael Mackey was buried in the local cemetery at St. Germain au Mont D'Or, by the local French curate of the Roman Catholic Church of the village.