Berberian made his debut in 1958 with the Turnau Opera in Woodstock, New York, as Don Magnifico in Rossini's "La Cenerentola". In 1963 he was promoted from the chorus to singing roles with the NYCO, beginning with Leandro in "The Love for Three Oranges" in April of that year. He sang several more roles with NYCO through 1967, including Collatinus in "The Rape of Lucretia", the Commandant in "Don Giovanni", the Major-Domo in "Capriccio", Osmin in Mozart's "Abduction from the Seraglio", and Tiresias in "Oedipus rex" among others. He later returned to the NYCO in 1977 to create the role of Gene Henderson in the world premiere in Leon Kirchner's "Lily".