Born in Vankleek Hill, Ontario, Harkin was named Commissioner of the recently created Dominion Parks Branch in 1911, and over a period of 25 years organized a nation-wide system of parks. A firm believer in the recreational and economic value of parkland, he directed his efforts to ensure access to the system for the greatest possible number of Canadians. Harkin was an ardent conservationist who was responsible for important advances in the field of wildlife preservation. On his advice the Historic Sites and Monuments Board of Canada was created in 1919, and he was one of its original members.