| Regimental number | 2420 |
| Place of birth | Wangaratta Victoria |
| Religion | Roman Catholic |
| Occupation | Labourer |
| Address | Hansonville, Victoria |
| Marital status | Single |
| Age at embarkation | 22 |
| Next of kin | Brother, Thomas O'Brien, Hansonville, Victoria |
| Enlistment date | 15 May 1915 |
| Date of enlistment from Nominal Roll | 12 May 1915 |
| Rank on enlistment | Private |
| Unit name | 14th Battalion, 7th Reinforcement |
| AWM Embarkation Roll number | 23/31/3 |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board RMS Persia on 10 August 1915 |
| Rank from Nominal Roll | Driver |
| Unit from Nominal Roll | 1st Division Train |
| Fate | Returned to Australia 12 April 1919 |