Réjean Poirier's musical studies were completed at the Montreal and Toulouse conservatories with renowned masters such as Bernard Lagacé, Kenneth Gilbert and Xavier Darasse. He was awarded First Prizes in organ and chamber music and won, at the end of his studies, First Prize at the J.S. Bach International Competition in Bruge.
Upon returning to Montreal in 1974, he founded, together with Christopher Jackson and Hélène Dugal, the Studio de musique ancienne de Montréal, and acted as its joint Artistic Director for nearly fifteen years. In 1990, he put together the Da Sonar ensemble. He is also a co-founder of two organ recitals series: Pro Organo and Les Concerts d'orgue de Montréal.
Dean of the Faculty of Music of the Université de Montréal from 1998 to 2006, Réjean Poirier teached harpsichord and organ and continues an international career on both instruments. He has played regularly with ensembles such as the Studio de musique ancienne de Montréal, Les Violons du Roy, Tafelmusik Baroque Orchestra, the Orchestre symphonique de Laval and the Orchestre symphonique de Montréal. He has recorded extensively both on organ and harpsichord as a soloist and chamber musician.