He was trained as an organist by Henri Gagnon at Université Laval and also studied piano with Germaine Malépart in Quebec City.
[1] In 1961 Lagacé returned to Canada when he was appointed organist of the Cathedral-Basilica of Notre-Dame de Québec; a post he held until his retirement in 1993.
Simultaneously, he worked as the assistant director of the music school at Université Laval from 1971 through 1978.
When Pope John Paul II visited the Cathedral-Basilica of Notre-Dame de Québec in 1984, Lagacé performed the world premiere of Roger Matton's Tu es Petrus.
He performed several times on the CBC Radio programs 'Récitals d'orgue and Tribune de l'orgue, and he recorded Marius Cayouette's Hymne pascal on the LP Hommage à Henri Gagnon (1974, Alpec Records).