With the death of Mary Baillieu, the State Library of Victoria has lost one of its most active supporters and forceful advocates. She joined the Friends of the State Library of Victoria in 1969, and later, served on its Committee. She was appointed to the Library Council of Victoria, now the Library Board of Victoria, in 1986 and chaired the Promotions and Fund-raising Committee until 1991. Thereafter, she maintained her contribution to the Library as an Emeritus Member of the Board until her death.

Mary was determined that the Library should become the central focus for history and culture in Victoria and all her efforts were directed towards raising public consciousness of the resources of the State Library. In 1992, Mary, with the assistance of an active committee, launched the enormously successful Renaissance Appeal to elicit sponsorships of millions of dollars from Melbourne's corporate sector, and the achievements resulted in increased financial support for the Library. The State Library of Victoria Foundation succeeded the Renaissance Appeal and, largely due to Mary Baillieu's efforts, if continues her fund-raising activities.

An artist herself, Mary showed a particular interest in the La Trobe Picture Collection and its staff. She was a model patron and an interested provider of support in the most practical way, an example of this being her generous donation of funds to acquire the Library's major collection of portraits of Aboriginal people by Percy Leason. It is also notable that she helped find the money from the Sidney Myer Fund to start the Library's image database, Pictoria. As this is one of the largest databases of its kind in Australia, all those interested in using historic images as primary source material are in her debt.

In 1993, Mary Baillieu was named a member of the Order of Australia in recognition of her many activities as a patron of the arts, especially of the State Library of Victoria.

Her charm, grace, wit and loyalty are qualities which were admired by many, and were the attributes of a great personality. She will be greatly missed by all who knew her.