Born near Port Talbot, Upper Canada, Pearce joined the Department of the Interior in 1874 as a surveyor in Manitoba and the North West Territories. For almost thirty years as the Department's senior officer in the West, he played a major role in planning and implementing the government's policies for settlement and development of the region. He was responsible for important mining and irrigation legislation, and was instrumental in establishing Canada's first National Park at Banff. In 1904 Pearce joined the C.P.R., but continued to serve as a consultant on western development till his death at Calgary.