He was born in Saint-François on the Île d'Orléans, Canada East, the son of Louis Asselin and Marie Laperrière, and was educated at the Séminaire de Québec and the Université Laval.
Asselin was called to the Quebec bar in 1870 and set up practice in Rimouski.
He was defeated by Édouard-Onésiphore Martin when he ran for reelection in 1886, also losing a by-election in 1889 and then elections for the Quebec assembly in Matane in 1890 and in Rimouski in 1908.
He was a founder and director of the newspaper Progrès du Golfe.
In 1914, he was named a repatriation officer at Biddeford, Maine for the Canadian government, charged with encouraging former Quebec residents who had emigrated to the United States to return to Quebec.