Robert Wallace studied at the University of Edinburgh, which awarded him the degrees Master of Arts (MA) and Doctor of Laws (LLD). He was elected a Fellow of the Royal Scottish Geographical Society and a Fellow of the Royal Physical Society of Edinburgh, and became a member of the Highland and Agricultural Society of Scotland and of the Royal Agricultural Society of England. In 1879 he was a member of a farmers delegation to Canada.
Wallace was appointed professor of agriculture at the Royal Agricultural College, Cirencester, in 1882. In 1885 he became professor of agriculture and rural economy at the University of Edinburgh, a position which he retained until his retirement in 1922. During these years he investigated the agriculture of Italy and India (1887); Australia and New Zealand (1889); the United States (1879, 1890, 1893, 1898, 1907-1910); Egypt (1891); Greece (1891-1892); South Africa (1895); Canada and Mexico (1907); Rhodesia (now Zimbabwe, 1908); and Tonkin, the Malay States, Java and Canada (1910, 1923). On the basis of these and other investigations he published numerous articles and lectures, as well as a number of books, including Farm live stock of Great Britain (1885, with a fifth edition in 1923), Indian agriculture as seen by Robert Wallace... (1887), India in 1887 as seen by Robert Wallace (1888), and The rural economy and agriculture of Australia and New Zealand (1891). He was furthermore the editor of the autobiography and correspondence of Miss Eleanor Anne Ormerod* (1904).
Wallace was invited by the government of the Cape Colony to investigate its agriculture and farming practices, and arrived in 1895. He travelled all over the colony, at first accompanied by the agriculturalist C. Eustace Pillans*, but for most of his travels by the Colonial Veterinary Surgeon, Dr Duncan Hutcheon*. He also visited the Orange Free State (now the Free State), Transvaal, and Natal. The information he collected was written up in the form of a book, Farming industries of Cape Colony (London, 1896, 552p), an extensive review, in popular form, of agriculture and animal husbandry in the colony.
Wallace's visit to Rhodesia was at the request of the British South Africa (Chartered) Company (which administered the territory at that time), to which he remained a consulting adviser for five years.