| Date of birth | |
| Place of birth | Victoria, Hong Kong |
| Religion | Presbyterian |
| Occupation | Clergyman |
| Address | Mooroopna, Victoria |
| Marital status | Married |
| Age at embarkation | 54 |
| Height | 6' 0" |
| Weight | 196 lbs |
| Next of kin | Wife, Mrs A O'Sullivan, 'The Manse', Mooroopna, Victoria |
| Previous military service | Served for 2 years in the Field Artillery, South Australia. |
| Enlistment date | |
| Rank on enlistment | Chaplain (4th Class) |
| Unit name | Chaplains' Corps |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board HMAT A20 Hororata on |
| Rank from Nominal Roll | Captain |
| Unit from Nominal Roll | NIG |
| Promotions |
Captain Unit: Chaplains' Corps (Presbyterian) Promotion date: |
| Fate | Returned to Australia |
| Other details | Medal: British War Medal |
| Sources | NAA: B2455, O'SULLIVAN Horatio Eugene Augustus |