MacDougall was active as a playwright and screenwriter, and delivered from the mid 1930s to the early 1960s, several templates and scripts for about 30 film and television productions. Several of his pieces were filmed.
In 1953 he was diagnosed with multiple sclerosis. In the course of the disease he developed his own diet plan that had a certain influence on society and, according resulted in an improvement in his condition. At the time of his illness he was a professor at the University of Southern California in the field of theater.