He appeared frequently on Hollywood radio series, including Escape, playing lead roles and alternating with william Conrad as the opening announcer of Suspense in the late 1940s, and parts on Gunsmoke (doing an impersonation of Howard McNear as Doc Adams for at least one episode, "The Cast"), and Crime Classics. One of his few starring roles in this medium was as Jethro Dumont/Green Lama in the 1949 series The Green Lama, as well as a syndicated anthology series The Player, in which Frees narrated and played all the parts.