| Regimental number | 4899 |
| Place of birth | Melbourne Victoria |
| Religion | Presbyterian |
| Occupation | Commonwealth servant |
| Address | 26 Tenth Avenue, Maylands, Western Australia |
| Marital status | Single |
| Age at embarkation | 24 |
| Next of kin | Father, Mr K L T Siefken, 26 Tenth Avenue, Maylands, Western Australia |
| Enlistment date | |
| Rank on enlistment | Private |
| Unit name | 11th Battalion, 15th Reinforcement |
| AWM Embarkation Roll number | 23/28/4 |
| Embarkation details | Unit embarked from Fremantle, Western Australia, on board HMAT A38 Ulysses on |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 51st Battalion |
| Fate | Returned to Australia |
| Family/military connections | Brother: 354 Pte Otto John SIEFKEN, 3rd Machine Gun Company, died of disease while a prisoner of war, Germany, 21 October 1918. |
| Other details |
War service: Western Front Medals: British War Medal, Victory Medal |