Schallert appeared in supporting roles on numerous television programs starting in the early 1950s, including four episodes (and three different characters) in "Dick Powell's Zane Grey Theatre" between 1958 and 1961. He was in three episodes of "The Rifleman" and four episodes of "Gunsmoke" : season 3, episode 16 "Twelfth Night" in 1957, season 4, episode 16 "Gypsum Hills Feud" in 1958, and as Col. Grant in season 7, episode 27 "Wagon Girls" in 1962, and banker Ezra Thorpe in "The Money Store" season 14, episode 14. Schallert portrayed farmer Sam Becker in a 1961 episode of "The Andy Griffith Show", whose newborn son is delivered by Andy. He appeared in "The Partridge Family" as a very humble folk-singing guitar player in "Stage Fright" in 1971. He appeared three times as Major Karl Richmond on NBC's "Steve Canyon", starring Dean Fredericks in the title role.