Gertrude Mack, the youngest daughter of Jemima (nee James) Mack and the Rev'd Hans Mack, was born at Morpeth, New South Wales, and lived as a child in various parts of Sydney including Windsor, Balmain and Redfern. She was educated at Sydney Girls' High School.
Like her older sisters
Louise Mack and
Amy Mack, Gertrude Mack became a writer, known in both Australia and the United Kingdom. Her obituary in the
Sydney Morning Herald (6 April 1937), states that Mack's 'short stories and sketches were invariably the outcome of personal contacts. She could paint engaging pictures of people and places, and make them real to her readers'. Mack also translated stories from Russian, collaborating with Serge Ivanov to publish in English a volume of N. A. Baikov's tales for children.
Mack spent eight years in London, returning to Australia - seriously ill - only weeks prior to her death. She died in a private hospital in Darlinghurst and was buried at the Northern Suburbs Crematorium.
Mack is an aunt of
Nancy Phelan (q.v.); a diary of Mack's is included in Phelan's papers at the State Library of New South Wales.