Art left school for good at the age of 14 to enlist in the 177th (Simcoe Foresters) Battalion of the Canadian Expeditionary Force on February 22, 1916. Standing at a height of 5 feet 10 inches, he successfully persuaded the recruiting sergeants that he was 18 years old. He received basic training at Camp Borden and left Canada from the Port of Halifax via the S.S. Metagama on May 1, 1917. After a 13-day journey across the Atlantic Ocean, Art arrived in England and was transferred to the 3rd Reserve Battalion along with the rest of the 177th. He was promoted to an Acting Lance Corporal upon his arrival in England but requested a reversion to Private on August 11, 1917. On August 13, 1917, Art was transferred to the Central Ontario Reinforcement Depot, where his true age was finally discovered. A little over a month later, he was sent back to Canada and discharged on January 11, 1918, due to Army Council Instruction No. 1,186 for being underage. According to Art’s War Service Gratuity application, he later joined the Royal Air Force, but this has not been independently verified. For his service during World War I, he was awarded the British War Medal. 
By October 1919, Art was living in Southern California where he would soon begin a successful career in show business as a stuntman, makeup artist, and actor. On January 7, 1934, Art married an actress named Elinora Agnes “Gloria” McEniry, who used the stage name Gloria Stratton, at the Saint Catherine of Siena Catholic Church in Laguna Beach, California. The marriage produced four children: John Thomas Dupuis, Patricia Louise Dupuis, Ronald James Dupuis, and Pamela Lee Dupuis. Art became a naturalized citizen of the United States on October 8, 1943.
Art died of a heart attack on April 18, 1952, in Los Angeles, California, and was buried in Calvary Cemetery. During his storied, decades-long career, he appeared in more than 100 films, including “The Mark of Zorro” (1940), “Citizen Kane” (1941), “Joan of Arc” (1948), “Samson and Delilah” (1949), “An American in Paris” (1951), and “The Greatest Show on Earth” (1952), among others. He also worked on several television shows, including “The Cisco Kid,” “The Roy Rogers Show,” and “I Love Lucy.”
