Mercure was born Marie Lise Monique Émond in Montreal, Quebec, the daughter of Eugene and Yvonne (née Williams) Emond.

Her parents enrolled her as a young child in diction, tap dancing, musical theory and cello classes.

The couple had three children;[3] their daughter Michèle also worked as an actress, most notably in the films Kid Sentiment and A Scream from Silence (Mourir à tue-tête).

[5] Messages of condolence were conveyed by Canadian prime minister Justin Trudeau, Quebec premier François Legault, and Montreal mayor Valérie Plante.

Trudeau praised Mercure for how she "helped promote Quebec cinema beyond our borders", adding that "her legacy will live on through her work".