Mary Durack, born in Adelaide, South Australia, to Michael Patrick Durack and Bessie Durack (née Johnstone), and her siblings lived at the remote "Argyle" and "Ivanhoe" cattle stations in the Kimberley region of Western Australia.

The Durack family were pioneers in the settlement of the area by Europeans. The story of her family's history, beginning with the mid-19th century migration from Ireland, is presented by Durack in Kings in Grass Castles, and its sequel, Sons in the Saddle.

In 1935 the sisters, Mary and Elizabeth Durack, were to publish their first collaboration. The text in All About: The Story of a Black Community on Argyle Station was supplied by Mary and the illustrations were by Elizabeth. The collaboration was to produce a number of children's books: Chunuma in 1936; Son of Djaro and the Way of the Whirlwind in 1940—1941;The Magic Trumpet in 1946 and To Ride a Fine Horse (1963).

Durack wrote under the name "Virgilia" for The West Australian during 1937—38, a column for women and children in rural areas.

In 1950 she wrote the novel Keep Him My Country. Other important works include the saga of the Durack family, Kings in Grass Castles (1959) and its sequel, Sons in the Saddle; and a play, Swan River Saga: Life of Early Pioneer Eliza Shaw (1976). A biography, To Be Heirs Forever, also used Eliza Shaw as a subject. Durack also continued to write children's literature, most notably the story of the Nyungar man, Yagan, which was published in 1964 as The Courteous Savage: Yagan of the Bibbulmun. , and Tjakamarra: Boy between two worlds.

Other works by Mary Durack included a two—act play, Ship of Dreams; an Australian Settler (1968); The Rock and the Sand (1969) is a history of missionaries in the state; The Aborigines in Australian Literature (1978) is part of the non-fiction component of her work, a subject often forming the basis of many of her works of fiction.

On 2 December 1938 she married the aviator, Captain Horrie Miller, OBE, who died in 1980. They had six children including one daughter Robin Miller who became a famous aviator and nurse and became known as "The Sugarbird Lady" after her work fighting polio.

Her sister was artist and writer Elizabeth Durack and her father was noted Kimberley pioneer Michael Patrick Durack (1865—1950).

Durack was appointed a Dame Commander of the Order of the British Empire (DBE) for her services to literature on 31 December 1977. On 12 June 1989 she was appointed a Companion of the Order of Australia (AC).