Jean Paul Lemieux was born in Québec City in 1904. He studied at École des beaux-arts de Montréal from 1925 to 1929. Starting in 1931, he exhibited his work at a variety of annual events, such as those of the Art Association of Montreal and the Royal Canadian Academy of Arts.

In 1934, he became a professor at École des beaux-arts de Montréal. He began teaching at the École du meuble de Montréal in 1935. In 1935, he started to publish articles in newspapers and specialized magazines defending the social function of art, denouncing the conservatism of French Canadian society, and deploring how little the arts were encouraged in the country.

In 1937, he took a job teaching drawing and painting at the École des beaux-arts de Québec, a position he would keep until he retired in 1965. In 1951, Lemieux won first prize at the provincial art contest for his painting, The Ursuline Nuns .

In 1954, Lemieux received a grant from the Royal Society of Canada, and spent a sabbatical year in France.

In 1957, he made a remarkable impression on the Canadian art world. The National Gallery of Canada acquired several of his paintings. He also participated in several major contemporary art exhibitions. In 1958, Lemieux, along with some other artists, was chosen to represent Canada at the Brussels World's Fair. During that year, he also showed his work in Pittsburgh, Paris and Mexico. In 1960, eight of Lemieux's recent paintings were part of the Canadian section of the Venice Biennale.

In 1965, after 28 years of teaching at the École des beaux-arts de Québec, Lemieux retired and dedicated himself entirely to his painting. Starting in 1966, official recognition of his career intensified.

He was elected member of the Royal Canadian Academy of Arts in 1966 and received a medal from the Canada Council for the arts in 1967. He was named Companion of the Order of Canada in 1968. The Société Saint-Jean-Baptiste awarded him the Prix Philippe-Hébert in 1971, and the Canada Council for the Arts gave him the Molson prize in 1973.

Four universities granted him honorary degrees: Laval (1969), Bishop's (1970), Université de Montréal (1980) and Concordia (1985). In 1967, in honour of the Confederation, the Musée des beaux-arts de Montréal dedicated a major retrospective to him, which then travelled to Québec City and Ottawa. In 1974, the Ministère des Affaires culturelles du Québec presented an exhibition of his works in Moscow, Leningrad, Prague, and Paris.

Lemieux died on December 7, 1990 at the age of 86.