Michael Liddy is somewhat of a man of mystery. He was born in Fallas Green, County Limerick, Ireland, probably in March 1885, as Michael Augustine O'Dwyer, but when he came to Australia or when and why he changed his name, is unknown. In 1916, when he enlisted, he was 31 years old and working as a Law Clerk with Mr. W. Murphy, solicitor, of 60 Queen St., Melbourne. He was single and apparently had no family in Australia, naming Mr. Murphy as his next of kin. He lived at 543 Victoria Parade, East Melbourne.

After training at Royal Park, then Castlemaine, he was sent overseas, embarking for the war on board HMAS Suffolk A 23 on 16 April, 1916, arriving at Suez on 11 May. He was then with the 15th Training Battalion, intended as reinforcements to the 57th Battalion. On 19 May, he was at Tel-El-Kebir and taken on strength with the 57th Battalion. From there, he was sent via the Ivernia on 21 June, 1916, to join the British Expeditionary Force at Alexandria, then on to France, disembarking at Marseille on 30 June, 1916. On 21 July, he was taken on strength with the 59th Battalion. 

The 59th Battalion faced its first major battle on 23 July, the disaster of Fromelles.  Placed in the first wave of attack on the German forces, heavy casualties were suffered as the German machine gunners mowed down the ranks of soldiers crossing No Man's Land. For the next two months, Michael Liddy and his fellow soldiers were n and out of the front line, before being withdrawn in the winter of 1916-17.

Life in the trenches was cold, wet, and insanitary. Michael Liddy fell sick  on 19 August and was treated for two days at the 15th Field Ambulance Station for dermatitus and seborrhea. He was discharged to his unit on 8 September and rejoined them the following day. The skin condition continued to trouble him: he was admitted to hospital on 16 September, this time with excema, rejoining his battalion at the front on 29 September.

While his health was perhaps uncertain in the conditions of the trenches in winter, Liddy was apparently regarded as a good soldier. He was promoted to Lance Corporal on 23 February, 1917, and then to full Corporal on 22 June. By this time, the 59th had taken part in the advance against the Germans at Amiens, pushing the enemy back towards the Hindenburg line. They were not in the front line, but were active in defending the gains made at Bullecourt in May.

In July, 1917, Michael Liddy was recalled to England, having been placed on the Supernumery List and detached  for duty in England. He was placed with the 15th Training Battalion at Tidworth and then sent for further training from 16 August- 15 September at the Rifle Course Musketry School, Tidworth, qualifying 1st Class. He remained at Tidworth, and on 11 November, was placed with the Overseas Training Battalion, before heading back with them for active service in France on 29 December and rejoining his regiment on 11 January, 1918.

He was not long at the front: on 18 February, he was diagnosed with Fununculosis and admitted to the 2nd General Hospital and on 11 March, was transferred to England and placed in the Middlesex War Hospital. The condition was extremely painful and was characterised by outbreaks of boils caused by the infection of hair follicles, which form pus-infected lumps. The condition is recurrent and, with no antibiotics at that time, hard to recover from. He was transferred to a convalescent hospital, Hyland's hospital at Chelmford, on 28 March, 1918, and following his recovering, given two weeks leave. He reported to Australian military headquarters in London on 13 April, where he was assigned to the Overseas Training Brigade at Hurdcott, proceeding to France with them on 21 May.

By 7 June, he was back with hsi battalion in France, but on 20 July, was again ill for a week, rejoining the battalion on 27 July. His health seems to have held up, perhaps because it was summer by then. The tide of war had turned by then and Germany was on the point of collapse, but on 3 September, Michael Liddy was wounded in action, probably at Polygon Wood, where the 59th was heavily engaged. He was admitted to the No. 6 General Hospital at Le Havre, then sent back to England. On 10 February, 1919, he was transferred to the Australian Convalescent Depot and, on 1 July, was returend to Australia on board the Karmala, disembarking in Melbourne on 17 August, 1919. From there, he disappears: did he revert to his real name? Or did he remain Michael Liddy? He does not appear in the Electoral Rolls under either name, and in the Marriage and Death Lists, his name is not distinctive enough to establish where he lived or died.