William left from Montreal, Ontario, on 30 October 1917, and arrived in England on 19 November. Once there, he was first transferred to the Canadian Machine Gun Brigade, then to the 1st Canadian Reserve Battalion. He was sent to France and began his service in the 72nd Battalion Canadian Infantry on 8 March 1918.
He wasn't in France long before he saw action. 10 days after being assigned to the 72nd, his battalion was sent to relieve the 38th battalion on the front line, suffering heavy attacks and even a gas attack, which required some of the soldiers to wear gas masks for three hours straight. They stayed on the front line for five days, until they were in turn relieved and sent to support other unites in Cite St. Pierre and Cite Calonne. On the 27th of March, they were moved to Sains-en-Gohelle.
The next day, the unit was marched through mud, rain and sleet to Verdrel, then took a train to Cubit Camp Neuville St. Vaast, where they stayed the night. The following day, the 72nd again took the front line, this time in the Gavrelle sector. During the fighting, William took a shrapnel wound to the face, and was evacuated, eventually landing at the 7th General Hospital (one of almost 20 such hospitals) in Étaples, France. Étaples was a major hub for the Canadian, British, Scottish, and Australian military during the war, and housed multiple hospitals, a training base, a detention center, and a supply depot, in addition to the hospitals. Because of the constant presence of soldiers coming and going, and the thousands of wounded being transferred and cared for, it was seen by many as a dark place. One visitor described it this way:
A vast, dreadful encampment. It seemed neither France nor England, but a kind of paddock where the beasts are kept a few days before the shambles … Chiefly I thought of the very strange look on all the faces in that camp; an incomprehensible look, which a man will never see in England; nor can it be seen in any battle, but only in Étaples. It was not despair, or terror, it was more terrible than terror, for it was a blindfold look, and without expression, like a dead rabbit’s.
William remained there recovering from his wounds for four months, before rejoining the 72nd Battalion on 12 August 1918. He saw several other engagements over the next several weeks, until the bitterest fight they participated in began on 27 September. His battalion was assigned the job of attacking a 1250-yard front, penetrating 3000 yards into enemy territory, and capture Sancourt and Blecourt. They fought against heavy machine gun fire and bombardment, and took Sancourt, and eventually Blecourt. The offensive lasted until 2 October, and cost the 72nd 11 officers and 376 other men, one of which was William Harris.
For his service, William's widowed mother Sarah received a memorial plaque and scroll. The plaque had William's name written on it, as did the scroll, which also had a message commemorating his sacrifice in the name of freedom. You can see them below.