| Regimental number | 15250 |
| Date of birth | |
| Place of birth | Toowoomba, Queensland |
| Religion | Roman Catholic |
| Occupation | Fireman |
| Marital status | Single |
| Age at embarkation | 19 |
| Height | 5' 8" |
| Weight | 140 lbs |
| Next of kin | Father, Michael Joseph Francis O'Brien, James Street, Valley, Brisbane, Queensland |
| Previous military service | Served for 4 years in Senior Cadets; 1 year in 7th Infantry, Citizen Military Forces. |
| Enlistment date | |
| Date of enlistment from Nominal Roll | |
| Place of enlistment | Brisbane, Queensland |
| Unit name | Australian Army Service Corps, 1st Anzac Mounted Division, 15th Reinforcement |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board HMAT Ormonde on |
| Rank from Nominal Roll | Driver |
| Unit from Nominal Roll | 1st Australian Mounted Division Train |
| Fate | Returned to Australia |
| Discharge date | |
| Other details |
War service: Egypt Commenced return to Australia from Suez on board HT 'Karoa', 8 April 1919; disembarked Brisbane, 15 May 1919; discharged (medically unfit), Brisbane, 30 May 1919. Medals: British War Medal, Victory Medal |
| Miscellaneous details | Name does not appear on Embarkation Roll. |
| Sources | NAA: B2455, O'BRIEN Joseph Francis |