He was elected to the Ontario legislature in the 1985 provincial election, defeating Progressive Conservative René Piché in Cochrane North, a large riding in the province's northeastern corner. Fontaine was the only Liberal MPP elected from northern Ontario, and was appointed to cabinet as Minister of Northern Affairs and Mines. In October 1985, Fontaine announced that the Ministry would be reorganized as the "Ministry of Northern Development and Mines". He said the government would spend an additional $100 million in the north on development projects. Bud Wildman criticized the announcement as a one-shot infusion and that after five years there would be no more money.