| Regimental number | 3466 |
| Place of birth | Heidelberg Victoria |
| Religion | Roman Catholic |
| Occupation | Police constable |
| Address | Ascot Vale, Victoria |
| Marital status | Single |
| Age at embarkation | 25 |
| Next of kin | Father, John Francis O'Callaghan, 8 Hoddle Street, Essendon, Victoria |
| Enlistment date | 2 May 1916 |
| Rank on enlistment | Private |
| Unit name | 2nd Pioneer Battalion, Reinforcement 8 |
| AWM Embarkation Roll number | 14/14/4 |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board HMAT A7 Medic on 16 December 1916 |
| Rank from Nominal Roll | Lance Corporal |
| Unit from Nominal Roll | a corps Signal Company |
| Fate | Returned to Australia 16 June 1919 |
