| Regimental number | 6834 |
| Place of birth | Triangle Flat, Rockley, New South Wales |
| School | Triangle Flat Public School, New South Wales |
| Religion | Roman Catholic |
| Occupation | Shearer |
| Address | Triangle Flat, Rockley, New South Wales |
| Marital status | Single |
| Age at embarkation | 29 |
| Next of kin | Father, T Byrnes, Triangle Flat, Rockley, New South Wales |
| Previous military service | Nil |
| Enlistment date | |
| Rank on enlistment | Private |
| Unit name | 3rd Battalion, 22nd Reinforcement |
| AWM Embarkation Roll number | 23/20/3 |
| Embarkation details | Unit embarked from Sydney, New South Wales, on board HMAT SS Port Nicholson on |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 3rd Battalion |
| Fate | Killed in Action |
| Place of death or wounding | Broodseinde Ridge, Passchendaele, Belgium |
| Age at death | 31.10 |
| Age at death from cemetery records | 29 |
| Place of burial | Tyne Cot Cemetery (Plot XXXVIII, Row B, Grave 22), Passchendaele, Belgium |
| Panel number, Roll of Honour, Australian War Memorial | 35 |
| Miscellaneous information from cemetery records | Parents; Thomas and Ellen BYRNES, Wattle Grove, Triangle Flat, New South Wales |
| Family/military connections | Brother: 3785 Lance Corporal George BYRNES, 18th Bn, killed in action, Bapaume, France, 25 February 1917. |
| Other details |
War service: Western Front Medals: British War Medal, Victory Medal |