During his third year on the "The Andy Griffith Show" (1960) he suffered a massive stroke that greatly affected his left shoulder, most of his left arm and his legs. In earlier episodes, he is seen freely walking about. All episodes after this time either have him photographed in close-up, sitting or, secretly, propped up by a brace.
Portrayed Charles "Doc" Adams on CBS Radio's "Gunsmoke" (1952-1961).