Weatherwax made his acting debut in the early 1960s when he was nine years old, playing a boy named "Chester" in Gleem toothpaste commercials alongside Alice Pearce. He was then cast as Pugsley Addams on The Addams Family, after successfully auditioning with stars Carolyn Jones and John Astin. The program ran for two seasons from 1964 to 1966. After its cancellation, Weatherwax found he was typecast as Pugsley and lost interest in acting. He entered the U. S. Army at seventeen, and at the age of 21, he reprised the role of Pugsley in the 1977 reunion film Halloween with the New Addams Family. He established a career behind the camera as a movie studio grip and set builder, while making occasional appearances at Addams Family-related events with former costar Lisa Loring, who had played Pugsley's younger sister Wednesday Addams on the show.