In the early 1900s, Swain had his own stock theater company, the Mack Swain Co., which performed in the western and midwestern United States. His most notable residency, was in Santa Cruz, California, where at one point he was bringing in 6,000 patrons a week to see his performances; over two-thirds the population of the city at the time. On June 24, 1907, the Mack Swain Co. had its 61st show in 50 days, breaking the record by any theater company ever appearing in Santa Cruz. That same year Swain bought the Alisky Theatre, and changed its name to Swain’s Theatre. By 1913, audience attendance had begun to dry up and with it Swain's theatrical career. Mack was initially hesitant to work in the film industry, viewing it as an "inferior art form to theater," but eventually gave in after many of his fellow actors and peers had done the same.
