Austen, descended from Austrian grandparents, attended school in Brisbane and took up work as a clerk with the Customs Office and later was employed by he Queensland Public Library. During World War I he served with the Australian Army Medical Corps (1st Field Hospital) in Egypt, Gallipoli, Greece and Flanders.
Austen changed his birth name, Rudolf Novak Augstein, to 'Peter Austen' by deed poll in 1917. He returned to Egypt in 1920 and there changed his name again; this time to Aly Azie-l-Dinh. He also converted to Islam. Austen died in Cairo in 1939 without ever returning to Australia.
Austen was one of three brothers who served in the AIF during World War I. All three changed their surname to Austen.