| Regimental number | 257 |
| Place of birth | Brisbane Queensland |
| Other Names | William Halladay |
| Religion | Presbyterian |
| Occupation | Mine manager |
| Address | Oakey, Queensland |
| Marital status | Married |
| Age at embarkation | 27 |
| Next of kin | Wife, Mrs Elizabeth Ruddick, South Street, Toowoomba, Queensland |
| Enlistment date | |
| Rank on enlistment | Sergeant |
| Unit name | Mining Corps 1, Company 1 |
| Embarkation details | Unit embarked from Sydney, New South Wales, on board HMAT A38 Ulysses on |
| Rank from Nominal Roll | Sergeant |
| Unit from Nominal Roll | Mining Corps |
| Fate | Killed in Action |
| Date of death | |
| Place of burial | Railway Dugouts Burial Ground (Transport Farm) (Plot VI, Row P, Grave No.29), Zillebeke, Belgium |
| Panel number, Roll of Honour, Australian War Memorial | 27 |
| Other details |
War service: Western Front Medals: British War Medal, Victory Medal |