| Regimental number | 6544 |
| Place of birth | Brisbane, Queensland |
| School | Bundaberg State High School, Queensland |
| Religion | Roman Catholic |
| Occupation | Station hand |
| Address | George Street, Bundaberg, Queensland |
| Marital status | Single |
| Age at embarkation | 18 |
| Next of kin | Father, T 0'Neill, George Street, Bundaberg, Queensland |
| Enlistment date | |
| Rank on enlistment | Private |
| Unit name | 15th Battalion, 21st Reinforcement |
| AWM Embarkation Roll number | 23/32/2 |
| Embarkation details | Unit embarked from Brisbane, Queensland, on board HMAT A36 Boonah on |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 15th Battalion |
| Fate | Died of wounds |
| Place of death or wounding | France |
| Age at death | 20 |
| Age at death from cemetery records | 20 |
| Place of burial | Trois-Arbres Cemetery, (Plot I, Row Z, Grave 35), Steenwerck, France |
| Panel number, Roll of Honour, Australian War Memorial | 77 |
| Miscellaneous information from cemetery records | Son of Thomas and Mary Ann O'Neill, George Street, Bundaberg, Queensland |
| Family/military connections | Brother: Timothy James O'NEILL, Lance Corporal 1208, 11th Light Horse, killed in action 7 November 1917; Brother: John Alphonsus O'NEILL, Sergeant 3649, 42nd Bn, returned to Australia 2 January 1919 |
| Other details |
War service: Western Front Medals: British War Medal, Victory Medal |