In 1959, McGiver appeared in the episode "The Assassin" of NBC's espionage drama Five Fingers, starring David Hedison. In 1962, he appeared as Gramps in the episode "The Seventh Day of Creation" of the NBC medical drama about psychiatry, The Eleventh Hour, starring Wendell Corey and Jack Ging. He appeared in the Alfred Hitchcock Presents episodes "Six People No Music" and "Fatal Figures", and the Twilight Zone episode "Sounds and Silences". In 1971 he guest-starred in Alias Smith and Jones (season 1, episode 8, 'A Fistful of Diamonds'). In 1966, he appeared in Man's Favorite Sport?, which starred Rock Hudson and Paula Prentiss. Between 1963 and 1964, McGiver appeared in five episodes of The Patty Duke Show as J.R. Castle, who was Martin Lane's boss at the fictional newspaper The Chronicle.