Nielsen's career began in dramatic roles on television during "Television's Golden Age", appearing in 46 live programs in 1950 alone. He said there "was very little gold, we only got $75 or $100 per show." He narrated documentaries and commercials and most of his early work as a dramatic actor was uneventful. Hal Erickson of Allmovie noted that "much of Nielsen's early work was undistinguished; he was merely a handsome leading man in an industry overstocked with handsome leading men." In 1956, he made his feature-film debut in the Michael Curtiz-directed musical film "The Vagabond King". In the "Seattle Post-Intelligencer", Nielsen remembered Curtiz as "a sadist, a charming sadist, but a sadist". Nielsen called this film ""The Vagabond Turkey"". Though the film was not a success, producer Nicholas Nayfack offered him an audition for the science-fiction film "Forbidden Planet", resulting in Nielsen's taking a long contract with Metro-Goldwyn-Mayer (MGM).