After working as a model and posing for artists such as Arthur William Brown he gained connections in the modeling business and he started his own modeling agency, located in the Chrysler Building, in 1929. As the Walter Thornton Modeling Agency grew, it was considered one of “Big Three”, the largest model agencies in the United States, along with its competitors, John Robert Powers and Harry Conover. His agency worked with famous models such as: Lizabeth Scott, Susan Hayward, Grace Kelly, Lauren Bacall, Hazel Brooks, Lucille Wilds, and Eleanor Cahill. Walter Thornton supplied models to Alex Raymond for his comic book, Flash Gordon. A special autobiographical issue depicts Alex Raymond sketching panels using Walter Thornton model Patricia Quinn as a reference. Starting in the mid-50’s and continuing after Walter moved to Mexico, Walter Thornton modelling schools and agencies were opened in Canada.