Jack Bush was a member of the Canadian Group of Painters. The Group of Seven disbanded in 1932, one of the reasons being that they wanted to expand the Group - thus the Canadian Group of Painters was formed. Along with fellow artist J.W.G. (Jock) MacDonald, Jack Bush's paintings from the 1930s and early 1940s continued this Canadian landscape style. Both artists would go on to form part of the now famous modern group, Painters Eleven.

Bush began his career as a commercial artist. Echoing the experience of many members of the Group of Seven, employment in design and illustration for advertising accounts paid the bills with something left over for evening art classes. Until about 1940, by which time he was living in Toronto, Bush's studio work consisted of mostly small-scale paintings emulating the style and subject matter of the Group of Seven and the Canadian Group of Painters.

Earlier generations of Canadian artists had found the means or opportunity to travel abroad for exposure to late 19th century academic masters including works by Impressionists and Post-Impressionists. For Bush, his exposure to the works of Borduas, Jackson Pollock and Robert Motherwell, and his first visit to the Museum of Modern Art in New York in 1950 were to influence and encourage his growth as an abstract painter. Consequently, by the late 1940s his works became more expressionist in execution and more ambitious in both subject and scale.

Having participated in numerous group exhibitions, particularly in association with the Ontario Society of Artists and the Canadian Society of Painters in Water Colour, Bush had his first solo exhibition in the fall of 1949.