Born in 1891, Forsyth enlisted with the New Zealand Expeditionary Force shortly after the outbreak of the First World War. Serving with the New Zealand Engineers as a sapper, he participated in the Gallipoli Campaign and later fought on the Western Front. By August 1918, he was on probation to become a commissioned officer and was temporarily attached to an infantry battalion. On 24 August 1918, during the Second Battle of Bapaume, he played a key role in eliminating a machine gun nest that was holding up the advance of his battalion, but was then killed by a sniper. For this action, he was posthumously awarded the VC.