Canada's most famous contralto, Maureen Forrester, began her vocal studies with Sally Martin in Montreal and later studied with Frank Rowe and Bernard Diamant. Her first professional appearance came in a recital at Montreal in 1953, and she began a musical collaboration with pianist John Newmark which lasted until his death in 1991. In 1955 she went to Paris for a recital, and her New York debut recital was one year later. That recital brought her to the attention of Bruno Walter who asked her to sing the contralto solos in the Second Symphony of Mahler with the New York Philharmonic the following season. This appearance was the beginning of her international fame, as Walter considered her an outstanding interpreter of Mahler's music. During the early years of her career, she concentrated on concert and recital programs. Her first important operatic appearance came in 1962 at Toronto in Gluck's Orfeo ed Euridice. In 1966 she debuted at the New York City Opera as Cornelia in Handel's Giulio Cesare with Beverly Sills and Norman Treigle. She made her Metropolitan Opera debut as Erda in Das Rheingold in 1975. Her excellent comic timing brought critical acclaim for her appearances as the Step-Mother in Massenet's Cendrillon, the Witch in Hansel and Gretel and as the Fairy Queen in Sullivan's Iolanthe at Stratford. In her later years, she was in great demand as the Countess in Tchaikovsky's Queen of Spades and in Poulenc's Dialogues des Carmelites.
From 1965 to 1974, she was a member of the Bach Aria Group and made many tours of the United States and Canada with that group. Her solo recital tours took her around the world and, ever a staunch supporter of Canadian composers, she regularly included their songs on her programs. The most important of the works she championed was Fleming's The Confession Stone. Although her orchestral repertoire ranged from Bach and Pergolesi to Elgar and Casals, it was as an interpreter of Mahler that Forrester is best remembered, most especially for the Second Symphony and Das Lied von der Erde. Maureen Forrester's voice was a dark, rich contralto, but with an ease in the upper register which allowed her to sing some mezzo-soprano parts including the Verdi Requiem and Brangäne in Wagner's Tristan and Isolde. Although a large voice, it was very flexible which created a demand for her in the oratorios of Bach and Handel, as well as other Baroque composers, which she sang all over the world. In the 1960s and 1970s, she averaged around 120 performances a year, while raising five children.
Forrester enjoyed teaching, and from 1966 until 1971, she headed the voice department at the Philadelphia Academy of Music. After leaving the Academy of Music, she continued to teach privately in Toronto and to give master classes in conjunction with her recitals. In 1983, she began a five-year term as chairman of the Canada Council for the Arts. She published her autobiography, Out of Character, in 1986, the same year she was named a Companion of the Order of Canada. Maureen Forrester remained one of the great contraltos of the twentieth century throughout her long performing career.