Stanley Cosgrove was born in Montreal on December 23, 1911. He completed his classical studies with the Pères de Sainte-Croix and in 1929 attended the School of Fine Arts where he was taught by Joseph Saint-Charles, Edwin Holgate and Charles Maillardé. In the thirties, he obtained a certain amount of success on the Montreal Art scene. In 1939 he obtained a grant from the Quebec Government to study in Paris but war erupted and Cosgrove went to New York instead.
He then went to Mexico where he studied at the San Carlo Academy with the great masters Rodriguez Lozano, Jose Clement Orozco and Rivera. He then worked with the great Jose Clemente Orozco as his assistant.