Sydney George Harding was born on 16 April 1918 in Woolwich, London, United Kingdom to Mr and Mrs A. Harding of Charlton, London.

He enlisted in the Royal Navy, training at H.M.S. Pembroke, Chatham before joining H.M.S. Encounter as a Gun Layer in July 1941. Soon after, Encounter was transferred to the Eastern Fleet based in Singapore and was tasked with intercepting Japanese invasion convoys in February 1942.

Encounter was sunk on 1 March 1942 in the Second Battle of the Java Sea along with H.M.S. Exeter. Sydney was among just over 800 survivors picked up by Japanese forces and imprisoned at Macassar on the Island of Celebes as forced labour.

Sydney died on 16 April 1945, aged 27 and was buried in Ambon War Cemetery in plot 31.A.6.