She gave her debut recital at the local YWCA in 1953. She made her concert debut in Beethoven’s Ninth Symphony with the Montreal Symphony Orchestra under Otto Klemperer.

She toured extensively in Canada and Europe with Jeunesses Musicales. She made her New York City debut in Town Hall in 1956. Bruno Walter invited her to sing for him; he was looking for the right contralto for a performance and recording of the Mahler Symphony No. 2 “Resurrection”. This was the start of a warm relationship with great rapport. Walter had been a student of Mahler, and he trained Forrester in interpretation of his works. She performed at Walter’s farewell performances with the New York Philharmonic in 1957.

In 1957, she married the Toronto violinist and conductor Eugene Kash. The couple had five children, including actors Linda Kash and Daniel Kash. Forrester converted to Judaism.

She performed regularly in concert and opera. At the New York City Opera, she sang Cornelia in Handel’s Giulio Cesare (1966), opposite Norman Treigle and Beverly Sills, which was recorded by RCA in 1967. She sang at the Metropolitan Opera in New York in 1975 in Das Rheingold (Erda), Siegfried, and Un ballo in maschera. Forrester also provided the voice of the Bianca Castafiore character in the television series The Adventures of Tintin. She was a strong champion of Canadian composers, regularly scheduling their works in her programs, especially when she toured abroad. A notable example is composer Donald Steven, whose work “Pages of Solitary Delights” (winner of the 1987 Juno Award for Classical Composition of the Year) was written for Ms. Forrester. From 1983-88 she served as Chair of the Canada Council.

In 1986, she co-authored her autobiography, Out of Character ( ISBN 0-7710-3228-5), with journalist Marci McDonald.

Maureen Forrester died on June 16, 2010, aged 79, in Toronto, after a long battle with dementia. She was predeceased by Eugene Kash, her former husband, whom she had divorced in 1974, and who died in 2004. She was survived by her five children.