Sydney resided at 17 Knightrider Street Maidstone and enlisted with the 1st Home Counties RAMC TF on the 18th March 1915. He was sent to France on 23rd January 1917 and arrived at Le Havre on 24th January 1917 and served with the 2/1st Home Counties FA. Whilst attached to the 3/4 Queens regiment he sprained his ankle whilst pushing the water cart. He was discharged on 21st August 1919.