Watson was born in Oakland, California and grew up on a ranch near Stockton. His father was a sheep rancher and his mother a school teacher. His grandparents were from Texas. He attended Franklin Elementary School and graduated from Elk Grove High School in 1958. His family did not have a television during his childhood and like most families of that era listened to the radio for news and entertainment. After high school he went to San Francisco State University for two semesters where he studied acting for a short time under Victor French.