In 1961, Buntrock won the role of Harold "Sport" Baxter on the sitcom Hazel, starring Shirley Booth. The series aired for five seasons, first on NBC with Don DeFore and Whitney Blake in the role of Harold's parents, George and Dorothy Baxter. In the fifth and final season (1965-1966) shown on CBS, the series was retooled after DeFore and Blake were dismissed and Harold lived with his Uncle Steve Baxter (Ray Fulmer), Aunt Barbara (Lynn Borden), and cousin Susie (Julia Benjamin). During the run of Hazel, Buntrock was tutored on the set and attended Lake Marie Public School in Whittier when the show was on hiatus.