Sam was born Allison Samuel Hall in Carrollton, Ohio, and graduated from Dartmouth and Yale. A veteran of the World War II Battle of the Bulge, Sam Hall was married to Dark Shadows star Grayson Hall in 1952. Their son, Matthew, later worked with his father on scripts for the soap opera One Life To Live as well as the 1991 Dark Shadows series. Despite many scenes from that series being liberally adapted from his work, Hall did not receive screen credit until Episode 4.