Born in Drummondville, Quebec, Gosselin studied at the Institut des arts graphiques in Montreal and then worked as a printer. He joined the NFB's title department in 1956 to design titles and credits. The French team was in the process of expanding, and he met with many of the talented filmmakers and technicians working there. He then worked as an assistant cameraman, location manager and assistant editor before photographing his first film, Gilles Groulx's Golden Gloves (1961).
After photographing many of the most notable Quebec films of the 1960s he directed his first feature film in 1971: the odd science-fiction movie for children Le martien de Noël; it was his only fiction film outside of his documentary output. It was working as cinematographer on many films by Pierre Perrault that began his special interest in the Aboriginal and folk cultures of Quebec. This interest inspired his two most important films as a director: César et son canot d'écorce (1971) and Jean Carignan, violoneux (1975).[ From 1977 to 1980 Gosselin in collaboration with Léo Plamondon photographed and/or directed a series of short films on traditional Quebecois craftspeople for the NFB titled La belle ouvrage.
Bernard Gosselin won a Canadian Film Award in 1968 for his black-and-white cinematography on Perrault's Le Règne du jour (1966). He died on March 20, 2006 in Saint-Bernard-de-Lacolle, Quebec.