Born at Cox's Creek, Auckland, New Zealand, on 3 March 1872, Mabel Hill was the youngest of the nine children of Charles Hill, a hatter, and his wife, Eliza Ann Hulbert. The family had arrived from Australia not long before her birth, and moved to Wellington in 1875.
Initially the family lived in premises on Lambton Quay from which Charles operated his business. Mabel attended the Terrace School, but the corporal punishment administered to her and her brother Alfred induced her parents to move them to Thorndon School. She did not attend a secondary school but after three years in standard six went to the newly founded Wellington School of Design to study art. As pupil and teacher she remained there from 1886 until 1897, by which time the institution had expanded its scope to become Wellington Technical School.
One of her colleagues was the Scot J. M. Nairn, whose knowledge of contemporary movements in European art and commitment to impressionism influenced her. A trip with him and others to Australia in July 1897 helped convince Mabel to go to Paris to study. However, her conviction faded when she discovered that her fiancé, the Dunedin printer John McIndoe, was building a house for them in Macandrew Road, Dunedin. On 12 January 1898 she and McIndoe were married at St John's Presbyterian Church, Wellington. She moved to Dunedin where she was to live for most of the next 50 years.
Mabel joined the Otago Art Society at a time of change: W. M. Hodgkins, founder of the Dunedin Public Art Gallery, died in 1898; Girolamo Nerli had left Dunedin two years earlier; Grace Joel and Frances Hodgkins were soon to go overseas. Mabel Hill effected a small change by exhibiting and working under her birth name, while sitting on council under her married name. This confounded the society's practice of indicating women's marital status in their catalogues.
A small studio had been built for her in the house in Macandrew Road, and to this she would retreat to paint while her children were small. She and John McIndoe had three sons and a daughter. After John died prematurely in 1916 Mabel continued to paint. She exhibited in Dunedin, Christchurch and Wellington, and painted portraits and still lifes. She had her studio at home enlarged, and also painted at Brighton (where she had a summer home) and made sketching trips to other parts of Otago. Gardening was another passion, and she made many flower paintings, including illustrations to Barbara Douglas's Pictures in a New Zealand garden (1921). She took private pupils and taught art at Archerfield College, a private secondary school for girls, from 1922 to 1925. With A. H. O'Keeffe, she opened the Barn Studio in Carroll Street in the early 1920s.
When her children had grown up, her desire to travel resurfaced. Between 1926 and the outbreak of the Second World War she travelled extensively, taking every opportunity to paint in the plein air style beloved of her most significant mentor, Nairn. In 1926 she visited her son Archibald in the United States, and returned with new energy. She spent most of 1927 in Tahiti, and about 1928 went to Europe. She painted at Concarneau, Brittany, with Sydney Thompson, and spent 1931 at Capri. From 1932 to 1934 she lived mostly in London, renting a studio and making trips to France, Germany and Russia. She was back in Dunedin from 1934 to 1938. In 1937 she received King George VI's Coronation Medal.
At the end of the war, aged 73, Mabel Hill left New Zealand to settle permanently in England, buying a house in East Grinstead, Sussex, near her son Archibald, by then a renowned plastic surgeon. She died there on 18 November 1956. She had been forced by failing eyesight to give up painting about 1951.
Mabel Hill's love of early impressionism coloured her opinion of the movements that followed it. Spending her formative years in New Zealand, then marrying and raising a family instead of studying in Europe as some of her contemporaries were able to do, limited her development as an artist. Although she frequently exhibited with most of the art societies in New Zealand, few of her best works have found their way into public collections. A retrospective of her work was mounted by the Dunedin Public Art Gallery in 1969. Her best watercolours, paintings of great freshness and transparency, are mostly in the private collections of her family and friends.