painter, was born on 23 December 1883 in Brighton, Victoria, youngest of the ten children of Francis Edward Stewart and Agnes, née Park. (Like her brother Francis, Janet adopted the surname Cumbrae-Stewart, except that she omitted the hyphen – unlike most auction houses and writers.) After sketching trips with John Mather , she studied at the National Gallery School, Melbourne in 1901-7 under Bernard Hall and Frederick McCubbin . In 1905 she came second in the National Gallery’s Travelling Scholarship competition, the winner being Isaac Cohen . She was a member of the Council of the Victorian Artists’ Society in 1914-16 and exhibited regularly with it from 1909 to 1919. She also exhibited with the Queensland Art Society in 1912, 1914 and 1915. In 1914 she sent work to the Panama-Pacific Exposition at San Francisco, which won a silver medal. Between 1920 and 1937 she exhibited at the Athenaeum Gallery, Melbourne.
In 1922 Cumbrae Stewart travelled to London with her sister Beatrice and began exhibiting at the Beaux Arts Gallery (1924-31), the Royal Academy, the Regent Gallery (Glasgow) and at the Old Salon, Paris, where in 1923 she was awarded an honourable mention. She travelled throughout Europe and to Canada. During her seventeen-year stay in Europe she lived at Chelsea, London, Avignon, Caen (France) and Laiguelia on the Riviera de Pononte, Northern Italy. She returned to Australia to visit her family in 1939 and remained when World War II broke out. From 1947 until her death on 8 September 1960 she lived at Margaret Street, South Yarra with her lifelong companion, Miss Argemore ffarington ('Bill’) Bellairs.