Early in his career, in the 1950s, Metzger worked primarily as a film editor and was a member of Local 771 of the IATSE. He was employed in editing trailers for Janus Films (now The Criterion Collection), a major distributor of foreign art films, especially those of Michelangelo Antonioni, Ingmar Bergman, Federico Fellini, Jean-Luc Godard and François Truffaut. In 1953, Metzger was credited as assistant director to William Kyriakis on the film "Guerilla Girl". In 1956, he worked on the dubbing of "And God Created Woman" starring Brigitte Bardot. His directorial film debut, "Dark Odyssey" (1961) (co-directed with Kyriakis), was a drama concerning the experiences of a Greek immigrant arriving in New York. The film was favorably reviewed by "The New York Times" and others. In 1959, he edited the film "The Gangster Story" starring Walter Matthau and, in 1960, Metzger was a presenter for the Japanese film "The Warped Ones".