| Regimental number | 26/500 |
| Occupation | Railway clerk |
| Next of kin | Father, Patrick O'Callaghan, 33 Owen Street Wellington |
| Rank on embarkation | Rifleman |
| Unit name | New Zealand Expeditionary Force, New Zealand Rifle Brigade, 4th Battalion, B Company |
| Embarkation details | Unit embarked from Wellington on |
| Sources | Nominal Roll Vol. 2: Roll 24, p. 24 |