During his career as a performer 1962-73, Grenier participated in concerts with the Karlsruhe SO, the CBC Quebec Chamber Orchestra, and the Quebec Symphony Orchestra and gave recitals in Karlsruhe, Paris, Quebec City, Shawinigan, Trois-Rivières, and Montreal. He premiered, among other works, 11/2 by Marcelle Deschênes in Montreal in 1968, and with the flutist Mario Duschenes he took part in the first Montreal performance of Boulez' Sonatine in 1969.
Grenier taught acoustics and piano at the St-Laurent Cegep 1967-74 and lectured on the piano and piano literature 1967-74 at the University of Montreal. His dissertation for his licentiate was entitled 'Sonate pour deux pianos de Bruce Mather'. He joined the Canada Council in 1974 and served as comptroller and program organizer until 1979, when he was appointed director of the CMM.
Author Louise Ostiguy