She was born Jacqueline Maranger in Sudbury, Ontario, to Ernest Marenger and Albertine Thanase, on September 20, 1928.
On September 8, 1953, at Notre-de-Dame-de-Grâce, Quebec, she wed the financier Paul Desmarais (1927-2013), also a native of Sudbury.
In 2011, she received an honorary doctorate from the Université de Montréal's faculty of music.
In 2013, Desmarais was named an officer of the Order of Canada. In 2016, she was awarded a Companion of Quebec's Order of Arts and Letters.
According to Forbes, Desmarais had a net worth of $4.2 billion in January 2015.
In 2016, Montreal's Sainte-Justine Hospital christened the Jacqueline Desmarais Pavilion.
Jacqueline Desmarais died on March 3, 2018, aged 89.