| Regimental number | 9/1085 |
| Address | Wingatui |
| Marital status | Single |
| Next of kin | Father, Denis O'Brien, Wingatui |
| Rank on embarkation | Trooper |
| Enlistment status | Volunteer |
| Unit name | New Zealand Expeditionary Force, 5th Reinforcements, Otago Mounted Rifles |
| Embarkation details | Unit embarked from Wellington on |
| Members of the 5th Reinforcement, Otago Mounted Rifles Regiment, departed New Zealand on board two ships, HMNZT 7 'Limerick' and HMNZT 10 'Arawa'. It is not possible from the Nominal Roll to determine on which ship an individual embarked. | |
| Final rank | Bombadier |
| Final unit | New Zealand Field Artillery |
| Fate | Killed in Action |
| Place of burial | Adanac Military Cemetery (Plot I, Row J, Grave No 30), Miraumont, France |
| Miscellaneous information from cemetery records | Parents: Mr & Mrs. Denis O'Brien, King Street, Mosgiel, Dunedin |
| Other details |
Medals: 1914-15 Star, British War Medal, Victory Medal |
| Miscellaneous details | Nominal Roll Vol. 1: Otago Mounted Rifles/Fifth |