William Paterson Ewen was born in 1925 in Montréal. He enlisted in the Canadian Army, serving in the infantry from 1943 - 1947. He later attended McGill University, taking drawing classes with John Lyman and met his future wife Françoise Sullivan, a dancer and artist. He engaged with Les Automatists during this time. His studies at McGill included geology and fine arts. Ewen transferred to the Montréal Museum of Fine Arts School of Art and Design in 1948, where Lismer and Goodridge Roberts were teachers. His influences and socializing with various artists exposed him to various artistic stlyes.
In 1950, two of Ewen’s works were exhibited by the Montréal Museum of Fine Arts in their 67th Annual Spring Exhibition, and at the same time, two works were shown in the l’Exposition des rebelles, organized by the Automatists.
In 1956, Ewen became a founding member of the Non-Figurative Artists’ Association of Montréal and began to exhibit abstracts with them at the Galerie Denyse Delrue.
In 1962, Ewen’s work was purchased by The National Gallery of Canada.
Ewen's marriage dissolved in the 1960's resulting in a downward spiral in his personal life. His 1973 self portrait 'The Bandaged Man' depicts his troubles of the time, it can be seen at The National Gallery of Canada.
Recovering in 1968 from hospitalization, Ewen moved to London, Ontario. He met several other artists and got back on his feet creating artworks. His work was exhibited at The Carmen Lamanna Gallery in Toronto and was included in the Seventh Biennial of Canadian Painting at the National Gallery of Canada.
He began collage work and explored mixed media incorporating fabric, metal, linoleum, nuts and bolts, and plywood. Using plywood and wood working tools became a popular practice for him.
He was awarded a Canada Council Senior Fellowship in 1971. His 1970's creations are often referred to as "phenomoscapes", they depict the weather and forces of nature.
Ewen taught at the University of Western Ontario in 1972, the Banff Centre for the Arts in 1976, and the Nova Scotia College of Art and Design in 1976 and 1977.
He represented Canada at the 1982 Venice Bienniale, and was given the National Award of the Banff School of Fine Arts in 1987, and the Toronto Arts Award in 1989. He is a member of The Royal Canadian Academy of Arts.
His work is widely collected both nationally and internationally, being represented in many collections including the Montréal Museum of Fine Arts, the Vancouver Art Gallery, the Art Gallery of Ontario, the National Gallery of Canada and the Museé du Québec.
He died in 2002.