Educated at Hurstpierpoint College, Austen-Smith joined the Royal Air Force Volunteer Reserve in 1943 during the Second World War.
41 Squadron, on 27 March 1945, and fought front line actions with 125 Wing through the Netherlands and Germany until the cessation of hostilities in May 1945.
He remained with the unit until 31 March 1946, and was promoted to flight lieutenant (war-substantive) on 7 April 1946, subsequently receiving an extended-service commission in the rank of flying officer on 15 August.
[20] Austen-Smith was awarded the Distinguished Flying Cross (DFC) in March 1953, for service during the Malayan Emergency.
[22] He was knighted as a Knight Commander of the Order of the British Empire, Military Division (KBE) in the 1979 Birthday Honours,[23] and as a Gentleman Usher to the Queen, appointed a Commander of the Royal Victorian Order (CVO) in the 1994 New Year Honours.