[1] At 20 years of age Smith was appointed headmaster of Invergordon Public School, in Easter Ross, but, due to an interest in physiology, he returned to Edinburgh University to study arts and science.
On completing his medical course in 1885 Smith was appointed assistant-professor of natural history, senior demonstrator of zoology at Edinburgh University.
In 1899 he was appointed physician to the infectious diseases unit at the hospital, Adelaide City Coroner, Inspector of Anatomy and chairman of the Central Board of Health.
[3] In 1901 during the South African War he was surgeon captain, Imperial Bushmen's Corps and officer in charge of plague administration at Cape Town.
[1] Smith was suspended from coronial duties in 1903 after 18 charges were laid against him of the misuse of human remains, specifically the removal of heads and the collection of skeletons for medical research,[3] including that of well-known and popular local identity, Tommy Walker.
[4] A board of inquiry headed by James George Russell found that Smith's actions had been "indiscreet" and he was dismissed from his position as coroner.
Smith was the author of The Aborigines of Australia, which was printed in volume three of the Official Year Book of the Commonwealth of Australia (1910), in which he criticised misrepresentation of Aboriginal people, suggesting review of "our knowledge of [their] beliefs and actions" and referring to them as the "most interesting [race] at present on earth and the least deserving to be exterminated by us and the most wronged at our hands".
His proposers were Sir William Turner, Daniel John Cunningham, Alexander Crum Brown and Cargill Gilston Knott.
[1] On his return to Adelaide, Smith resumed his duties at the board of health and contributed to the Australian Encyclopaedia, including a large part of the "Aborigines" article.
[8] Authorship of the book, which at the time was criticised as dominated by "white thinking"[7] has now been properly attributed to Unaipon and republished under his name as Legendary tales of the Australian Aborigines .
[13] In addition to numerous books, Smith also published pamphlets and contributed largely to scientific journals and Chambers Encyclopaedia.