In 1960 O'Malley made guest appearances on The Tab Hunter Show, The Law and Mr. Jones, Johnny Midnight, Johnny Staccato, Harrigan and Son, Adventures in Paradise, The Islanders, Going My Way, and The Tall Man. He made numerous guest appearances on CBS's Perry Mason, including as the defendant in the 1960 episode "The Case of the Prudent Prosecutor" and as the murderer in the 1961 episode "The Case of the Roving River".