| Regimental number | 727 |
| Place of birth | Bega, New South Wales |
| Religion | Roman Catholic |
| Occupation | Clerk |
| Address | 29 Stanley Street, Leichhardt, Sydney, New South Wales |
| Marital status | Single |
| Age at embarkation | 23 |
| Next of kin | Mother, Mrs Pauline O'Neill, 29 Stanley Street, Leichhardt, Sydney, New South Wales |
| Enlistment date | |
| Date of enlistment from Nominal Roll | |
| Rank on enlistment | Private |
| Unit name | Machine Gun Company 5, Reinforcement 13 |
| AWM Embarkation Roll number | 24/10/4 |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board HMAT A29 Suevic on |
| Regimental number from Nominal Roll | 727A |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 20th Battalion |
| Fate | Killed in Action |
| Miscellaneous details (Nominal Roll) | *Spelt Desmond Denis O'Neill on NR |
| Age at death from cemetery records | 24 |
| Place of burial | Hem Farm Military Cemetery (Plot II, Row J, Grave No. 20), Hem-Monacu, France |
| Panel number, Roll of Honour, Australian War Memorial | 92 |
| Miscellaneous information from cemetery records | Parents: Denis Lawrence and Pauline OINEILL, 29 Stanley Street, Leichhardt, New South Wales |