He is credited with writing the screenplay or story outline for over 25 films, including The Big Store (1941), The Great Morgan (1945), and Song of the Thin Man (1947), as well as several television series.
Perrin was a registered attorney who never practiced; he instead worked in the publicity department for Warner Bros. in 1930.
He often told the story of how he made his way into Groucho Marx's dressing room in 1931 with a forged letter of introduction from Moss Hart.
Groucho was impressed with Perrin, and arranged for him to be hired by Paramount Pictures for the film Monkey Business (1931).
Beginning in the late 1970s and well into his later years, Perrin taught screenwriting and film history at California State University Northridge.