He formed close relationships with Métis and francophone community leaders notably Joseph Dubuc and Louis Riel.
Cunningham was elected as a Liberal in the Marquette riding, defeating future Premier of Manitoba John Norquay.
Prime Minister John A. Macdonald noticed Cunningham's independent record and asked him to join the government caucus in 1873.
Cunningham was appointed as a member of the interim executive of the North-West Territories but died in Minnesota, while en route to take up his new position.
Following his death, Cunningham's opponent from the general election, Liberal Joseph Ryan, was declared to be the MP for the riding upon review.