While working on The Informer (1935) in Los Angeles, Campbell ordered several black-and-tan uniforms to be rented from a local uniform surplus vendor. Among the authentic uniforms that turned up was a haversack labeled S.C. Campbell, A Company, 18th Batallion. It was the very same item Campbell had work when he was fighting in the Canadian Army in WWI.
Moved to San Diego, California, in 1921, and entered the film industry in 1924 as an extra, earning $7 a day.
His wife, Margaret Baird Campbell, was a judge and former counter-espionage agent for the Royal Canadian Mounted Police.
Claimed to have worked on Hell's Angels (1930) as a flying sequences supervisor for only one week; he was fired by Howard Hughes over creative differences.