Born in Sydney to Lucy (née Armstrong) and (Sir) James Reading Fairfax, newspaper proprietor, Mary Elizabeth was the eldest of seven children and the only girl. From 1877 the family lived at Ginahgulla, with the exception of two years abroad, and from 1884 they spent the summer months at their country house in Moss Vale. Mary was educated at home.

Mary Fairfax never married and had no children. Known as Miss Mary from childhood, she became 'the quintessential maiden aunt' according to Caroline Simpson in the Australian Dictionary of Biography. Fairfax was, says Simpson, 'among the last of the great Victorians'. She was a foundation member of the executive of the Queen's Jubilee Fund in 1887, and was councillor of the University of Sydney's Women's College from 1893 until her death. She was associated with the RSPCA, the YWCA, the Kindergarten Union, and District Nursing Association (Sydney) and the Bush Book Club. She was a State council-member of the Girl Guides' Association. During both world wars Mary worked for the Australian Comforts Fund and the British (Australian) Red Cross Society. She joined the Victoria League in England and was a founder of its New South Wales branch in 1917. Mary was president of the Society of Arts and Crafts of New South Wales from 1912-19, and was a foundation member of the Sydney Symphony Orchestra Ladies' Committee in 1936.

In 1925, Lucy Fairfax passed away and Mary inherited the properties at Ginahgulla and Moss Vale, as well as 2,196 shares in John Fairfax & Sons Ltd, publishers of the Sydney Morning Herald. She took a keen interest in the paper and visited its offices regularly. She was known for her hospitality at Ginahgulla where she entertained leading society figures. During wartime her dining room was used to billet servicewomen.

Mary's 'spontaneous generosity' leads Simpson to surmise that 'the full measure of her philanthropy will never be calculated'. On her death, most of her £428,278 estate went to the Fairfax family, along with bequests to charities and employees, including £1,000 for the Women's College.

Sources used to compile this entry: Simpson, Caroline, 'Fairfax, Mary Elizabeth (1858-1945)', in Australian Dictionary of Biography Online, Australian National University, 2006, http://www.adb.online.anu.edu.au/biogs/A140137b.htm.