Born on November 30, 1888, in Winthrop, Massachusetts, Macgowan began his career as a drama critic. He wrote many books on modern theater, including The Theatre of Tomorrow (1921), Continental Stagecraft (1922) with Robert Edmond Jones, Masks and Demons (1923) with Herman Rosse, and Footlights Across America (1929). In 1922, he ran the Provincetown Playhouse as its producer, with Eugene O'Neill and Robert Edmond Jones as business partners. His close relationship with O'Neill lasted their lifetimes.[2]
In 1947, he left the movie industry to become the first chair of the Department of Theater Arts at UCLA. The theater building on the school's campus is named in his honor. Throughout his life, he wrote books on several subjects, including drama and film, most notably Behind the Screen, a history of cinema published posthumously in 1965.[2]
He died on April 27, 1963, in West Los Angeles, California, aged 74.