He enlisted in the Public Schools Battalion of the Royal Fusiliers, and was commissioned in February 1915 into the K.R.R.C. Commissioned Temporary 2nd Lieutenant Reserve Bn. on 22 Jul 1915 and appointed to the 21st Bn. on 2 Feb 1916, entered France on 2 Oct 1916. William went to France in October 1916, but was then posted with his regiment to Italy in September 1917. He had been acting Captain since 1916 and 3 days after his death official news was received that he had been made Captain. For three months during 1917, he was in hospital, at first in France and then at Reading in England, suffering from a knee injury from a riding accident and a bad attack of trench fever. On 21st March 1918, the first day of the big German offensive, he returned to France. On March 24th, the 181 K.R.R.C. were engaged in very heavy fighting at Bapaume. William was struck by a piece of shell and died instantaneously. On March 21st, the K.R.R.C. had approximately 900 men, but by the 30th they were down to just 80.