Morse guest-starred in more than a thousand drama, comedy, and talk-show presentations in the U.S., Canada, and Britain. Early American appearances include the "U.S. Steel Hour," "Encounter," and "Playhouse 90". He also guest-starred on such TV series as "Naked City", "The Untouchables", "The Twilight Zone", "Wagon Train", "The Defenders", "The Invaders", "The Starlost", and "The Saint". In "The Outer Limits" episode "Controlled Experiment", he starred with Carroll O'Connor and Grace Lee Whitney. In "The Starlost" episode "The Goddess Calabra", he guest-starred with John Colicos.