He was one of the four founding captains of the 48th Highlanders of Canada, which served in South Africa during the Second Boer War, and rose to become its commanding officer. At the beginning of World War I, he offered the Canadian Expeditionary Force the entire regiment, and the offer was accepted. Formally referred to as the "15th Battalion", it became known as the "Red Watch". He was in command at Neuve Chapelle, Ypres, and St Julien.