| Regimental number | 2367 |
| Place of birth | Woosang, Victoria |
| School | State School No. 3361, Victoria |
| Religion | Roman Catholic |
| Occupation | Farm labourer |
| Address | Korong Vale, Victoria |
| Marital status | Single |
| Age at embarkation | 21 |
| Next of kin | Father, David O'Brien, Korong Vale, Victoria |
| Enlistment date | |
| Rank on enlistment | Private |
| Unit name | 4th Light Horse Regiment, 16th Reinforcement |
| AWM Embarkation Roll number | 10/9/3 |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board HMAT A53 Itria on |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 8th Battalion |
| Fate | Killed in Action |
| Place of death or wounding | Ypres, Belgium |
| Age at death | 22.9 |
| Age at death from cemetery records | 22 |
| Place of burial | Menin Road South Military Cemetery (Plot II, Row AI, Grave No. 24), Ypres, Belgium |
| Panel number, Roll of Honour, Australian War Memorial | 54 |
| Miscellaneous information from cemetery records | Parents: David and Catherine O'Brien, Korong Vale, Victoria. Native of Woosang, Victoria |
| Family/military connections | Brothers: 163 Lance Corporal Dougald O'BRIEN, 1st Field Squadron Engineers, Anzac Mounted Division, died of disease, 7 November 1918: 655A Pte David Michael O'BRIEN, 39th Bn, returned to Australia, 5 April 1919. |
| Other details |
War service: Western Front Medals: British War Medal, Victory Medal |