George Marshall McCall Smith was born on 13 November 1882 at Nairn, Scotland, the second son of Ann Mein Andrews and her husband, Samuel McCall Smith, who farmed at Laggan, Speyside. He was educated at Laggan School, Elgin Academy and the University of Edinburgh, graduating MB, ChB in 1904, and was in general medical practice at Strathmiglo, Fife, and then in Perth. On 12 September 1907, at Tranent, he married Barbara Grieve. They had two sons and two daughters, but in 1914 Smith left for New Zealand with one of his patients, Lucy Margaret Scott. He took up practice in Nimmo Street, Rawene, and became superintendent of Rawene Hospital.
The isolated, poor Hokianga district was dependent on maritime transport, with few all-weather roads and no railway. Smith and his nurses travelled on foot and horseback, by coach and launch. The hospital's water supply, sewerage system, operating theatre and other amenities were inadequate, and its board was reluctant to authorise new expenditure. The large Maori population was suspicious of Pakeha medicine yet gravely in need of health services. The 1918 influenza epidemic put Smith on his mettle. To prevent the spread of infection he had shops closed, posted armed men at crossroads, and organised teams to feed the sick. These measures proved successful and recovery was rapid.
George and Barbara were divorced in February 1921, and on 14 March, in Auckland, he married Lucy. They were to have a son, John, who died in 1932, and a daughter, Janet. In 1921 Smith was dismissed by the Hokianga Hospital and Charitable Aid Board, which had tired of his hectoring them for improvements. Local opinion was aroused in his favour, however, and the dismissal was not implemented. Thereafter Smith became the dominant figure in the public life of the district. With the onset of the 1930s depression he became an ardent advocate of Douglas Social Credit.
In his primitive and isolated practice Smith placed emphasis on the important role played by nurses, and trained Lucy to be his anaesthetist. He berated the conservatism of other doctors, and was responsible for a number of innovations, including having nurses gowned, masked and gloved to prevent cross-infection; using cod-liver oil and Vaseline as a dressing; and using Nembutal for painless childbirth. He earned the respect of the Maori community through his concern for their welfare. In the mid 1920s Smith persuaded the board to build a new hospital. He was largely responsible for its planning and raised money for its equipment through a variety of means, including a local household tax and an illegal casino. When the new 40-bed hospital opened in 1928 it was reported to be the most up-to-date in New Zealand.
Smith's most notable achievement was the implementation in Hokianga of the Labour government's plans for a socialised health service. He adapted the concept of 'special areas' to produce a fully integrated health scheme in which education, prevention and treatment (both domiciliary and hospital) were provided free of charge to the local population. The doctors were employed on full-time salaries by the hospital board; and the district nurses, who had the primary responsibility for diagnosing and treating patients in their remote districts, were specially selected and seconded from the Department of Health. The whole system was under the control of the medical superintendent, Smith. After lengthy and sometimes stormy negotiations, the Hokianga special area was established in August 1941. With the strong support of the local community it survived the restructuring of the health system in the 1990s.
Smith retired from Hokianga Hospital in 1948 and went into general practice at Waikanae. He died there on 27 December 1958, survived by Lucy, who died in 1961, and his daughter Janet. A man of striking physical size and appearance – partly on account of his long hair and informal dress – Smith was keenly interested in the reform as well as the practice of medicine. He was well-read in literature and philosophy and found such people as Douglas Robb, A. R. D. Fairburn, Frank Sargeson and Vernon Brown to be kindred spirits. Fairburn described Smith as 'a cross between an Arab chieftain and an Archbishop'. During his life George Smith became a legendary figure in New Zealand as the archetypal 'backblocks doctor', and published several successful books based on his Hokianga experiences. He was a courageous, tempestuous, extraordinary man.