
| Regimental number | 25/667 |
| Date of birth | |
| Place of birth | Waikawa |
| Religion | Roman Catholic |
| Occupation | Farmer |
| Marital status | Single |
| Age at embarkation | 33 |
| Height | 5' 10" |
| Weight | 180 lbs |
| Next of kin | Mother, Mrs O'Brien, Slope Point, Southland |
| Previous military service | Nil |
| Enlistment date | |
| Place of enlistment | Trentham |
| Rank on embarkation | Rifleman |
| Unit name | New Zealand Expeditionary Force, New Zealand Rifle Brigade, 3rd Battalion, D Company |
| Embarkation details | Unit embarked from Wellington on |
| Final rank | Rifleman |
| Final unit | 3rd Battalion, New Zealand Rifle Brigade |
| Fate | Killed in Action |
| Age at death from cemetery records | 35 |
| Place of burial | No known grave |
| Commemoration details | Tyne Cot Memorial (New Zealand Apse, Panel No 7), nr Ieper, Belgium |
| Miscellaneous information from cemetery records | Parents: Jeremiah and Annie O'Brien, Slope Point, Southland. Native of Waikawa, Invercargill |
| Other details |
War service: Egypt, Western Front Embarked Wellington on board HMNZT 'Ulimaroa', 5 February 1916; disembarked Suez, 13 March 1916. Embarked Alexandria to join the British Expeditionary Force, France, 7 April 1916. Admitted to 3rd Canadian Casualty Clearing Station, 17 April 1916; transferred to General Hospital, Rouen, 30 April 1916 (suspected enteric); transferred to England, 11 May 1916, and admitted to Netley Hospital, 12 May 1916; transferred to Convalescent Camp, Addington, 9 June 1916; to NZ Command Depot, Codford, 4 September 1916; to Sling Camp, 11 November 1916. Rejoined unit in France, 1 January 1917. On leave to Paris, 13 August 1917; rejoined unit from leave, 21 August 1917. Wounded in action, 12 October 1917. Now, 15 November 917, reported wounded and missing, 12 October 1917. Court of Enquiry, 18 April 1918, concluded: 'Killed in action, 12 October 1917.' Note on file, Adjutant, 3nd Bn, NZ Rifle Brigade: Rfm. O'Brien went into action with the Bn at Passchendaele on 12th October 1917. He was reported as wnd & missing. No evidence forthcoming to show that he passed through Hospitals or any Mil Base since that day.' Medals: British War Medal, Victory Medal |
| Sources | Nominal Roll Vol. 2: Roll 24, p. 16 Archives New Zealand (Wellington), Agency AABK, Series 18805, File 21381338 |