Jean McEwen was born in 1923 in Montreal, and began painting in 1946 while studying pharmacy at the University of Montreal. His first solo exhibition in 1951, at Galerie Agnès Lefort in Montreal, was received favourably. After encouragement from Paul-Émile Borduas, McEwen traveled to Paris that same year and met with Jean Paul Riopelle in December. After a productive two-year trip in which he painted, visited public galleries and museums in Paris and Spain, exhibited with Riopelle and Sam Francis, traveled with Riopelle to Brittany and saw exhibitions by his New York contemporaries, McEwen returned to Montreal and began working for Frosst pharmaceutical company. He participated in many solo and group exhibitions in Quebec and Ontario in subsequent years, including his first solo show in Toronto at Gallery Moos in 1961, two overseas exhibitions in 1962 and a solo exhibition in 1963 at the Martha Jackson Gallery in New York.

The exhibition catalogue from the 1973 Musée d'art contemporain retrospective states, "he was one of the first Quebec artists to stress what was to become the major characteristic of Quebec art after Automatism, that is, the exploration of the dynamic possibilities of colour." This quote succinctly describes McEwen's painting; it is all about colour. Over the course of his career, McEwen experimented with different techniques in applying colour to his canvases. He turned to acrylic paint for a few years, experimented in hard-edge painting and explored various compositional formats for his abstract paintings, but the one constant in his work was his insistence on the importance of colour.

The National Gallery of Canada organized a traveling exhibition of his and Harold Town's work in 1966. In 1969 he became a member of the Royal Canadian Academy. He retired from Frosst in 1973 in order to paint full time, and the same year the Musée d'art contemporain in Montreal organized a retrospective of his work entitled McEwen 1953 - 1973. A Canada Council Award in 1977 allowed him to travel to Paris for nine months, and upon his return he began teaching part time at L'Université du Québec à Trois-Rivières (1980 to 1985) and Concordia University (1983 to 1995). The Montreal Museum of Fine Arts organized a retrospective of his work entitled Jean McEwen: Colour in Depth in 1987. McEwen died in Montreal in 1999.