Williams was hired by City Opera in 1946 to sing the leading role in Madama Butterflly. Her later roles with the company included Nedda in Leoncavallo's Pagliacci, Mimi in Puccini's La Boheme, and the title role in Verdi's Aïda.
She later appeared with the Metropolitan Opera, the Boston Lyric Opera, the Vienna State Opera, the Philadelphia Orchestra, the New York Philharmonic, and sang at the White House.
In 1951, she recorded the role of Bess in Porgy & Bess for Columbia Records, featuring Lawrence Winters as Porgy. Her other recordings included A Camilla Williams Recital and Camilla Williams Sings Spirituals.