Saint-Amand made the transition from opera to theatre by taking the role of Harlequin in Marivaux's play Le Jeu de l'Amour et du Hasard (The Game of Love and chance).
Afterwards, he played forL'enfer, c'est moi (Hell, it's me), the biographical story of Actress Néfertarie Bélizaire's childhood sexual abuse at the hands of her uncle in Haiti.
[1] In 2019, Mario Saint-Amand was a student at Laval University and an assistant researcher at the Quebec Addiction Rehabilitation Center and has been a spokesperson for Maisons Péladeau since 2014.
His first nomination took place at the presentation of Prix Gémeaux in 1992 following the interpretation of his character, Alain, suffering from schizophrenia in L’amour c’est pas assez (Love is not enough).
While still under the direction of Janette Bertrand, he gets re-nominated again in 1996 when he gets offered the role of Louis Côté in Un Peu, Beaucoup, À la Folie (A Little, Much, To the Folly) that he will play alongside Marcel Leboeuf and Macha Limonchik.