Ewing made her debut at the Metropolitan Opera in 1976 in Mozart's "The Marriage of Figaro". She starred as Carmen, Dorabella in Mozart's "Cosi fan tutte", Salome, the title role in "L'incoronazione di Poppea", Marie in Berg's "Wozzeck" and Shostakovich's "Lady Macbeth of Mtsensk". She also sang and appeared in Henry Purcell's "Dido and Aeneas".