Harvey first arrived in Canada in 1908 where he worked as a surveyor in northern Alberta and High River. On 18 May 1916 he enlisted in the 13th Regiment, Canadian Mounted Rifles, at Medicine Hat, Alberta. He was subsequently commissioned as a lieutenant and posted to the Western Front in 1916. He then transferred to Lord Strathcona's Horse, part of the Canadian Cavalry Brigade. Harvey was awarded the Victoria Cross following an incident on 27 March 1917 at the village of Guyencourt.