| Regimental number | 5063 |
| Place of birth | Bunbury, Western Australia |
| School | Balingup State School, Western Australia |
| Religion | Roman Catholic |
| Occupation | Farmer |
| Address | Nannup Post Office, Nannup, Western Australia |
| Marital status | Single |
| Age at embarkation | 27 |
| Next of kin | Father, Mr T Brennan, 127 Ford Street, Leichhardt, Sydney, New South Wales |
| Previous military service | Nil |
| Enlistment date | |
| Rank on enlistment | Private |
| Unit name | 11th Battalion, 16th Reinforcement |
| AWM Embarkation Roll number | 23/28/4 |
| Embarkation details | Unit embarked from Fremantle, Western Australia, on board HMAT A9 Shropshire on |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 11th Battalion |
| Fate | Killed in Action |
| Place of death or wounding | France |
| Age at death | 27 |
| Age at death from cemetery records | 27 |
| Place of burial | AIF Burial Ground, Grass Lane (Plot I, Row B, Grave No. 2), Flers, France |
| Panel number, Roll of Honour, Australian War Memorial | 61 |
| Miscellaneous information from cemetery records | Parents: Thomas and Elizabeth BRENNAN, 39 Thornley Street, Leichhardt, New South Wales. Native of Busselton, Western Australia |
| Family/military connections | Brother: 5062 Pte James BRENNAN, 11th Bn, died of wounds, 6 September 1916. |
| Other details |
War service: Western Front Medals: British War Medal, Victory Medal |