| Regimental number | 31623 |
| Religion | Roman Catholic |
| Occupation | Farmer |
| Address | Hornsdale, South Australia |
| Marital status | Single |
| Age at embarkation | 21 |
| Next of kin | Father, M F Leahy, Hornsdale, South Australia |
| Enlistment date | 21 August 1916 |
| Rank on enlistment | Driver |
| Unit name | Howitzer Brigade 23, Reinforcement 9 |
| AWM Embarkation Roll number | 13/133/3 |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board RMS Orontes on 23 December 1916 |
| Rank from Nominal Roll | Driver |
| Unit from Nominal Roll | 5th Field Artillery Brigade |
| Fate | Returned to Australia 1 July 1919 |
| Miscellaneous details (Nominal Roll) | *Spelt Marcellus Ambrose Leahy on NR |
