Avon Reah Smith-Ryan was born on 3 May 1908 at Northam, Western Australia, one of four children born to Thomas Smith-Ryan and Hilda Mary Reah. Prior to enlistment, Smith-Ryan worked as a Bank Officer in Perth, and married Grace Christina Clark on 23 December 1939 at Ross Memorial Methodist Church, West Perth.

He enlisted in the Australian Imperial Force at Claremont, Western Australia, on 21 November 1940 at age 32. Captain Smith-Ryan embarked from Australia for Malaya with the 2/4 Machine Gun Battalion on 30 December 1941 and arrived at Singapore on 26 January 1942. When Singapore fell to the Japanese a month later, he became a prisoner of war and was subsequently interned at Changi on 15 April 1942.

On 19 February, a few days after they were captured, a group of Australian soldiers faced a Japanese firing squad. A member of this group, Smith-Ryan was hit by a bullet under the left shoulder blade but escaped by pretending to be dead and eventually made his way to Singapore General Hospital where he received treatment. He was betrayed by a Japanese civilian, however, after leaving the hospital and re-joined his unit at Selarang Barracks in October 1942.

The Japanese surrendered on 15 August 1945, and Australian soldiers were repatriated two months later. Smith-Ryan arrived in Sydney aboard HMT Arawa on 6 October 1945. He was discharged on 18 January 1946 and later returned to work as a Bank Officer.

Avon Reah Smith-Ryan died on 13 December 1970 at Perth, aged 62.