Efa Prudence Heward was born in 1896. Heward's formal art training began with lessons at the school of the Art Association of Montreal (AAM), where she received instruction in drawing from William Brymner and landscape painting from Maurice Cullen. In 1912 Prudence won an AAM scholarship and continued her studies at the AAM. She exhibited her work, for the first time, at the AAM spring exhibition, in 1914.
In 1916, Prudence moved to England, with her mother and sisters, to be near her brothers who were in the armed forces. On her return to Montréal in 1918, Prudence resumed her studies at the AAM. From 1925-1926, she took classes in Paris. While there, she met Ontario painter Isabel McLaughlin and would later go on sketching trips to locales as varied as northern Ontario and Bermuda.

Heward's friendship with other women artists, such as McLaughlin and members of the Beaver Hall Group, was important because, at the time, the role for women in art was limited. She was later invloved in organizations such as the Canadian Group of Painters, which she co-founded in 1933. She also served as vice-president of the group for several years. In 1939, Heward was a founding member of the Contemporary Arts Society. Heward continued to exhibit her work and won a number of awards. In 1924, she exhibited for the first time at the annual exhibition of the Royal Canadian Academy [of Art]. Then, in 1929, she won the initial first prize in the Willingdon competition for her painting, Girl on a Hill. 

She was invited to exhibit with the Group of Seven. The first solo exhibition of her work was at the Scott Gallery in Montréal, in 1932. Several shared shows with fellow artists in the Beaver Hall Group followed: in 1934, in Toronto and Montréal; in 1940, in Toronto and in 1945, in Windsor.  In 1930, Heward's painting, Rollande, with its strong colours and the assertive stance of its figure, sold to the National Gallery. Throughout the 1930s, the painting won great acclaim outside Canada as part of travelling exhibits of Canadian art. 

Heward's lifelong frail health was exacerbated by a car accident, in 1939, and in the summer of 1945, she completed her last painting, Caladium. She died March 19, 1947. A memorial exhibition of Heward's work was shown at the National Gallery in March of 1948.