Léon Bellefleur was actively involved in the abstract art scene in Quebec from its early stages. Along with a number of his contemporaries, Bellefleur was interested in the surrealist preoccupation with the subconscious as a source of inspiration. He was an original member of the avant garde group Prisme d'Yeux, founded by Alfred Pellan in 1948. He was aware of the radical developments of the rival Automatistes, and in the late 1940s he found inspiration in the work of European abstract painters, especially Wassily Kandinsky and Joan Miró.

Galerie Walter Klinkhoff purchased paintings from Léon Bellefleur from the late 1950s and last held a one-man exhibition in 1985. Bellefleur’s work can be found in all the major Quebec-based museums, the National Gallery of Canada, and the McMichael Collection.