Marie-Nicole Lemieux began her career with significant Baroque roles, performing in works such as Orphée et Eurydice, Giulio Cesare, and Orlando Furioso. The development of her voice soon enabled her to explore the French repertoire of the 19th century (Les Troyens, Samson et Dalila, Carmen, Werther), Rossini (Tancrède, L'Italienne à Alger), Verdi (Falstaff, Le Trouvère, Un bal masqué), and Wagner (The Ring). Today, she graces the world's major opera stages (New York, Milan, London, Paris, Salzburg, Zurich, Vienna, Madrid, Brussels...) as well as in concerts and recitals, with a special focus on French and Russian melodies and German Lieder.

Her extensive and diverse discography has earned numerous accolades, and she records exclusively for Warner Classics. Recent and upcoming projects include Suor Angelica in Rome, Verdi's Messa di Requiem with the Orchestre National de France and at La Monnaie in Brussels, a concert tour with Les Violons du Roy, Mahler's Kindertotenlieder with the Orchestre Philharmonique de Radio France, Ravel's Shéhérazade with the Orchestre National de France, and Brahms' Rhapsody for Viola with the Danish National Symphony Orchestra.

Marie-Nicole Lemieux is a Chevalier of the Ordre des Arts et des Lettres of the French Republic, a Chevalier of the Ordre national du Québec, a Compagne of the Arts and Letters of Quebec, a member of the Order of Canada, and the Ordre de la Pléiade. She also holds an honorary doctorate from the Université du Québec à Chicoutimi.

At the Paris Opera: Falstaff (Mrs. Quickly), 2013, 2024; Jephtha (Storgè), 2018; Madame Butterfly (Suzuki), 2019