Born in August 16, 1849 in Brockville, West Canada, James Buchanan was raised in a family of Scottish immigrants: Alexander Buchanan and his wife Catherine. The Buchanan family returned to Scotland in 1850 before moving to Northern Ireland.
In 1863, when he was fourteen years old, Buchanan started working as a messenger at the offices of WM Sloane & Co, a shipping agency, where he made 10 £ a year. In 1868 he joined his brother William in Glasgow, to help him out in his hay, grains and seeds business. He worked there for ten years before leaving to London to become a sales agent at the whisky firm of Charles MacKinlay.