Daughter of Harry Emmerton, a solicitor who emigrated from England, and Alice Mabel Maude (née Balcombe), Mabel Balcombe Brookes was born in Victoria. She was educated mainly at home by her father and a series of governesses, after her mother withdrew her from kindergarten, worried that she was developing a bad accent. She spent a year at the family property, The Briars at Mt Martha, recovering from ill-health and while there developed an interest in Australian history and in Napoleon when he was exiled on St Helena. It was Mabel's maternal great-grandfather, William Balcombe, who had worked for the East India Company on the island of St. Helena and hosted Napoleon in his guest pavilion for two and a half months in 1815. In the later years of her life, Mabel would build on the family collection of Napoleonic memorabilia, eventually bequeathing the collection - comprising over 380 items - to the National Gallery of Victoria.

Mabel became engaged to Norman Brookes, a tennis player, who was the first Australian to win Wimbledon, at the age of eighteen, and married him in St Paul's Anglican Cathedral, Melbourne, on 19 April 1911. In 1914, with a baby daughter, she accompanied Brookes on his tennis trips to Europe and the United States of America. During World War I, in 1915, she joined her husband in Cairo where he was working as commissioner for the Australian Branch of the British Red Cross. She assisted in the establishment of a rest home for nurses. On her husband's posting to Mesopotamia, she returned to Melbourne in 1917. At this point she wrote three novels and continued to write on a variety of topics during her life.

In 1918 she served on the committee of the Royal Children's Hospital, then became president of the Children's Frankston Orthopaedic Hospital, the Anglican Babies' Home and the Society for the Prevention of Cruelty to Children. She was also an original member and a divisional officer of the Girl Guides' Association executive committee, foundation president of the Institute of Almoners and of the Animal Welfare League. She was a member of the Australian Red Cross Society's federal executive and president of the Ladies' Swimming Association.

Mabel Brookes's major contribution was as president of the Queen Victoria Hospital from 1923-1970, where she presided over the addition of three new wings within ten years.

During World War II the Brookes's home became a Red Cross convalescent home. The Brookes family lived in Elm Tree House and entertained Australian and American officers, including Lyndon Baines Johnson, later to become president of the USA. In a more practical contribution to the war effort, Mabel Brookes was commandant of the Australian Women's Air Training Corps and worked at the Maribyrnong munitions factory. She also attempted a political career by standing twice for parliament but was unsuccessful. She stood for the federal seat of Flinders in 1943 as a Woman for Canberra candidate and in 1952 for the state seat of Toorak for the Electoral Reform League.

She was appointed CBE in 1933 and DBE in 1955 for services to hospitals and charity. The French Government appointed her as Chevalier de la Legion d'Honneur in 1960 in acknowledgement of her gift to the French nation of the pavilion which Napoleon had occupied on her great-grandfather's estate on St Helena. Monash University conferred on her an honorary LLD in 1967. A travelling scholarship for opera singers was established in her name. Both Sir William Dargie and Clifton Pugh painted her portrait.

Mabel Brookes published her Memoirs in 1974. She died at South Yarra on 30 April 1975, survived by her two daughters.

Sources used to compile this entry: Poynter, J R, 'Brookes, Dame Mabel Balcombe (1890-1975)', in Australian Dictionary of Biography Online, Australian National University, 2006, http://www.adb.online.anu.edu.au/biogs/A130301b.htm.