Isobel Marion Dorothea Mackellar was born on 1 July 1885 at her family’s home, Dunara, on Point Piper overlooking Rose Bay in Sydney Harbour.

Dorothea was the third of four children and the only daughter of Sir Charles Kinnaird Mackellar, a physician and Parliamentarian, and his wife Marion (née Buckland). She received private tutoring in painting, fencing, and languages, and later attended lectures at the University of Sydney without formally enrolling. Fluent in French, German, Italian, and Spanish, Dorothea often served as interpreter during family travels. Her first significant loss was the death of her brother Keith in the Boer War.

The Mackellar family owned several properties in the Gunnedah area, including Kurrumbede and The Rampadells, about 25 km northwest of the town near the Namoi River.

Totalling more than 2,400 hectares (6,000 acres) in 1905. The family also owned Torryburn near East Gresford in the Hunter Valley, where Dorothea spent part of her childhood. Sir Charles later transferred the properties to his sons, Eric and Malcolm, who became respected members of the Gunnedah community. Dorothea frequently visited, staying with her brothers and maintaining her horse-riding skills. She was responsible for her ageing parents, and consequently wrote very little after her father’s death in 1926. She had acquired “Tarrangaua”, a splendidly located retreat at Lovett Bay on Sydney’s Pittwater, where she swam and read. Her mother died in 1933, and Dorothea divided her time mostly between “Cintra”, a house in Darling Point, and “Tarrangaua.”

Her brother MalcolMalcolm sold Kurrumbede in 1939, as there were no direct Mackellar descendants. Dorothea spent her final ten years in a Randwick nursing home, where her health declined. She outlived her younger brothers and died in her sleep on 14 January 1968. Her funeral was held at St Mark’s Church in Darling Point, where her poem “Colour” was read. According to her nurse, Adrienne Howley, Dorothea considered this poem her finest work. Her ashes were placed in the family vault at Waverley Cemetery in Sydney.