He was a founding member of the Non-figurative artist's association of Montréal, along with Claude Tousignant, Jean-Paul Mousseau, Guido Molinari, and Marcel Barbeau.

[2] Beginning in 1944, Ewen served in a reconnaissance regiment on the Western Front (World War II), but was not involved in active combat.

He studied geology, but after his first year he began to struggle with depression, and sought relief in copying magazine covers and sketching the landscape around Canadian Officers' Training Corps at Saint-Gabriel-de-Valcartier where he had re-enlisted for the summer.

Ewen sometimes recalled this period, caught up in Goodridge's orbit and the "sympathetic atmosphere," of the program, as "the happiest days of [his] life.

[3] Ewen's graduation that same year marked the end of his veteran's allowance, and so he went to work, first making hats, then selling rugs at Ogilvy's.

The grant allowed him to take a studio in Toronto, and this is where he developed his signature style, gouging landscapes out of massive plywood sheets with an electric router.

When Ewen returned to Toronto, his Beal Secondary job had gone to someone else, but there was an opening at the University of Western Ontario.

"[7][8] This began to change around 1949, when Françoise Sullivan's influence and the Automatiste milieu pushed Ewen towards abstraction.

This new way of painting balanced the psychic automatism of les Automatistes with the rising star of hard-edged geometric Plasticiens like Molinari and Tousignant, both of whom Ewen shared a studio with in the mid-1960s.