Walter Councill was born in 1915 in Camden, New Jersey. He moved to England with his parents, and later in 1924 they moved to Canada. Walter attended the Ontario College of Art.
For a year in a log cabin in northern Ontario, where he took numerous canoeing and painting trips. Coucill was mostly a self-taught artist but also learned from his many friends and companions including Charles Comfort, Fred Varley, Nicholas Hornyansky, Jack Martin, J.W. Beatty, André Lapiné and Alex Straker.
During World War Two he trained as a pilot with the Royal Canadian Air Force and was later appointed Art Director of the official Air Force magazine Wings. After the war he was art director of the Robert Simpson display department, art consultant, freelance designer and display designer for General Motors.
In 1964 he was commissioned by National Trust Bank to travel across Canada and paint all the provincial and territorial floral emblems in their natural habitats. He confided in botanists to ensure the accuracy of his subjects, the project took two years to complete. The collection is now housed at The National Archives.
Coucill became a member of the Royal Canadian Academy in 1978, he was also part of the the Arts and Letters Club in Toronto.
Walter Coucill is represented in the National Gallery of Canada, The National Archives, Art Gallery of Ontario, The University of Toronto, and The Supreme Court of Ontario. His works are in numerous private and corporate collections including.
Coucill died in 1982 at the age of 67.