Mayer was born and raised in a Franco-Ontarian family in Sudbury, Ontario. Mayer is fully bilingual and is proficient in German and Italian languages. His mother, Madeleine, worked as a legal secretary and his father, Gilbert, worked in advertising sales for local television and radio stations. He ran as a Liberal candidate in Nickel Belt in the 1974 federal election, and recorded comedic commentaries for CKSO-TV under the pseudonym "Marcel Mucker". Mayer's interest in art was encouraged by his uncle Réo who operated a small gallery in the basement of an army and navy store and was a hobbyist painter.
Mayer began his university studies in the history department at Carleton University. He later transferred to McGill University. where he completed a Bachelor of Arts degree with Honours in Art History.
Formerly, director and chief executive officer of the National Gallery of Canada. Mayer began this appointment on December 8, 2008. Mayer fulfilled two five year terms as director, and completed his mandate on January 18, 2019. During his tenure as director and CEO, he led many largescale acquisitions and oversaw numerous projects including the creation of the Canadian Photography Institute. He worked to increase the recognition of indigenous work with the opening of the Canadian and Indigenous Galleries in June 2017. Also that year, Mayer published Art in Canada, a book that celebrated Canadian and Canadian Indigenous artists. It was released to coincide with Canada's sesquicentennial. The book, designed by Paprika, won third prize in the Pictorial category for the 36th annual Alcuin Society Awards for Excellence in Book Design in Canada.
Prior to his appointment at the National Gallery of Canada, he served as director of the Musée d'art contemporain de Montréal (2004–2008) and The Power Plant in Toronto (1998–2001), as well as deputy director at the Brooklyn Museum in New York City (2001–2004) and curator of the Albright-Knox Art Gallery in Buffalo, New York (1994–1998). In Paris he was Head of Visual Arts with the Cultural Services of the Canadian Embassy and was a correspondent for the New York periodical Rizzoli’s The Journal of Art (1990 to 1993). In 1986 he began his career when named Assistant to the Director and later Assistant Director of the 49th Parallel Centre for Contemporary Canadian Art in New York (1986 to 1990).
- "The art world is failing to foster and manage creative talent". Retrieved 2020-02-22.
- "Sudbury native tapped for top post at National Gallery" Archived 2012-11-05 at the Wayback Machine, Ottawa Citizen, November 21, 2008.
- "Modern Man", Toronto Life, November 2000.
- "Mayer confirmed as gallery director" Archived 2008-12-15 at the Wayback Machine, The Globe and Mail, December 8, 2008.
- "National Gallery of Canada Bids Farewell to Director and CEO Marc Mayer", National Gallery of Canada Press Release, January 15, 2019.
- 2017 Award Winners Announced.