With an economic philosophy on parks development, Harkin led the Parks Branch into the business of selling Canadian scenery to tourists. Harkin identified the emergence of the automobile as a key component in driving tourism to Canada's national parks. Some notable commercial achievements Harkin made included motor vehicle legislation that permitted vehicles to enter parks, improvements of existing roads through parks, and major highway projects that connected more visitors to parks. His parks promotion strategy, favourable motor vehicle regulations, and improvements in accessibility notably increased tourism to Canada's national parks from 100,000 in 1921 to 550,000 in 1928.