James was educated at Dundee High School, and at Edinburgh and St Andrews Universities, qualifying in 1913. He held the post of resident house-surgeon at the Royal Infirmary, Dundee for a year, and began practice in Perth. He joined the R.A.M.C. in July 1915. He was the elder son of Robert Johnston of Dundee, M.B.C.M.; and the husband of Helen Mitchell McCormick of Dundee.