A voice actor best known for the many irascible characters he voiced for Hanna-Barbera Studios during the 1960s and '70s, John Stephenson had an arguably limited range - working with around six standard voices he would apply to various characters - but worked consistently in the field well into the late 20th century. Stephenson began his career as a live-action actor with numerous bit parts on TV shows in the 1950s, including appearances on "Perry Mason", "Gomer Pyle, United StatesM.C.", and "The Beverly Hillbillies". Possessing a gift for mimicry, including the ability to reference such iconic voices as those of Boris Karloff and Paul Lynde, Stephenson earned steady work at Hanna-Barbera Studios for over two decades beginning in the 1960s, voicing supporting and one-shot characters on popular animated shows like "The Flintstones", "The Jetsons", and "Scooby Doo, Where Are You!". Some of his most familiar characters include Fred Flintstone's boss Mr. Slate and Jonny Quest's father, Dr. Benton C. Quest.