| Regimental number | 14971 |
| Place of birth | Sydney, New South Wales |
| Religion | Roman Catholic |
| Occupation | Carpenter |
| Marital status | Single |
| Age at embarkation | 20.6 |
| Height | 5' 7.75" |
| Weight | 154 lbs |
| Next of kin | Mother, Mrs Annie O'Brien, 83 Buckland Street, Alexandria, New South Wales |
| Previous military service | Served for 18 months in the Australian Engineers, Citizen Military Forces. |
| Enlistment date | |
| Date of enlistment from Nominal Roll | |
| Place of enlistment | Sydney, New South Wales |
| Rank on enlistment | Driver |
| Unit name | August 1916 Reinforcements |
| AWM Embarkation Roll number | 14/42/2 |
| Embarkation details | Unit embarked from Sydney, New South Wales, on board HMAT A60 Aeneas on |
| Rank from Nominal Roll | Driver |
| Unit from Nominal Roll | Engineers Details |
| Fate | Returned to Australia |
| Miscellaneous information from cemetery records | Photo: Robert and Sandra Crofts |
| Discharge date | |
| Other details |
War service: England Commenced return to Australia on board HT 'Runic', 4 May 1917; disembarked Melbourne, 5 July 1917, for onward travel to Sydney; discharged (medically unfit: epilepsy), Sydney, 13 August 1917. Medal: British War Medal |
| Date of death | |
| Age at death | 31 |
| Place of burial | Rookwood Necropolis (Sec. R.C. 9, 2874), Sydney, New South Wales |
| Sources | NAA: B2455, O'BRIEN William Thomas |
