Margaret Berenice Price began singing lessons when she was nine, in Wales. At the age of 15 she won the Charles Kennedy Scott scholarship to the Trinity School of Music in London, where she studied with Scott for four years.
After graduation, she joined the Ambrosian Singers. She refused to enter competitions. While she was singing with the Ambrosian, her father wrote letters to opera companies to introduce her. She made her operatic debut as Cherubino in Mozart's Marriage of Figaro in 1962 with the Welsh National Opera. The next year, she was asked at the last minute to replace the indisposed Teresa Berganza in that same role. After that she formed an artistic partnership with James Lockhart, a conductor and pianist who became a vocal coach and accompanist and helped her in finding and judging repertory and formed a major recital team that was well known for its wide variety both as to language and style. She was particularly known for her interpretation of Schoenberg's Das Buch der hängenden Gärten. In 1967, she joined the English National Opera Group where she debuted in Mozart's short divertimento The Impresario, as Tytania in Britten's A Midsummer Night's Dream, and Galatea in Acis and Galatea. In the summer of 1968, she debuted at the Glyndebourne Festival Opera as Constanze in Mozart's Die Entführung aus dem Serail, which was widely acclaimed. Over the years, she went on to sing all of Mozart's major soprano roles at major houses and festivals around the world. She debuted at San Francisco in 1969 as Pamina in Die Zauberflöte, and her debut in Chicago was as Fiordiligi in Così fan tutte in 1972. She also chose Mozart's Don Giovanni for her German debut (1971 in Cologne). In 1973, she debuted at the Opéra de Paris, which she joined for that company's historic tour of the United States in 1976, where she sang Desdemona in Verdi's Falstaff. Typically for the time, the Metropolitan Opera was slow to secure her services. When she finally debuted there, in 1985, it was a triumphant portrayal of the same role. She says, by the way, that singing Mozart is all "sweat and labor" while Verdi, by comparison, is a "piece of cake." She often appeared on radio and television (including a memorable portrayal of Tchaikovsky's Tatyana and Salud in Falla's La Vida Breve). He active concert life is represented on disc by recordings of Ravel's Shéherazade with Claudio Abbado, and Elgar's The Kingdom under Sir Adrian Boult.
Margaret Price was named a Bayerischen Kammersängerin, received a CBE in 1982, and in 1993 was knighted as Dame of the British Empire.