The 1911 census records him as a laborer in the North Lanark Township farm of Elijah Giles and his wife Elizabeth. there is a record of the placement having been inspected on behalf of the Board of Guardians each year from 1911 to 1915 and again in 1917 when it is noted that he is on active service.
Sydney enlists in the Canadian Expeditionary Force in September 1915 giving his abode as Clayton, Ontario, his height is 5'6" and chest 35 inches when fully expanded.
He enlisted with the 18th Battalion and trained in Kingston, Napanee, Belleville and Halifax. Arriving in England in May 1916 he was a Bramshott camp until August that year and may have been able to visit his mother who died later in the year. The Battalion moved on to France and the trenches where he spent 13 months altogether. At Vimy Ridge in February 1917 he was wounded in the face, returned to duty and the following August received a shrapnel wound in the leg at the battle of Hill 70. He was sent to Lewisham Hospital, England, for treatment and then to Bromley convalescent home, where he spent three weeks before sailing for Canada.
He arrived at the home of Mr. and Mrs. Giles in February 1918 when a large reception was held in his honor. Although still lame and his wound not healed he went to work, and shortly afterwards was operated on for appendicitis in Renfrew hospital. After he recovered he went to Ottawa to learn harness making and shoe repair and was also taking a course to enter the civil service.
Sydney Catchpole died on September 21, 1918 with cause of death given as pneumonia; that was during the 1918 flu pandemic. He is buried at Ottawa's Beechwood Cemetery, in an area newly set aside for returning Great War veterans by Ontario's Soldiers Aid Commission, one of 98 Beechwood burials recorded in Commonwealth War Graves Commission files.