James Irvine-Smith (or Smith, James Irvine) qualified as a Member of the Royal College of Veterinary Surgeons (MRCVS) in Glasgow in 1898. He came to South Africa as a civil veterinarian in the Army Veterinary Division during the Anglo-Boer War (1899-1902). After the war, in 1902, he joined the South African Constabulary with the rank of Captain. On 16 February 1903 he attended the inaugural meeting of the Transvaal Veterinary Medical Association in Johannesburg and was elected its first President - and hence the first President of a veterinary professional society in southern Africa. He was re-elected as President for the next year, and from 1917 served as Vice-President until the association was transformed into the South African Veterinary Medical Association in 1920. After a year as Vice-President of the new association he served as its President from 1921 to 1924. In the latter year he was elected its first and only Honorary Life Vice-President.
In 1906 Irvine-Smith was attached to the Transvaal Civil Veterinary Department and in this capacity convinced the Johannesburg Municipality to erect a modern abattoir and ancillary facilities. When the abattoir was completed he became its first Director, a post he filled until his retirement in 1939. During World War I he established the South African Veterinary Corps and served as its commanding officer until 1916 when he returned to his civil duties. He served on several public bodies, such as the Government Railways and Harbours Board (1909, 1916 and 1923), the Agricultural Advisory Board (1920), as chairman of the Egg Export Commission (1925/26), and as a member of the South African Agricultural Union.