Robert Arthur Briggs Chamberlain was born in 1865 in Hull, Yorkshire, England. He was educated at Trent College, Nottingham; King's College, Cambridge, and the Universities of Heidelberg and Tübingen in Germany. He became a law student of the Inner Temple and then turned to journalism and worked on the Manchester Guardian and various London newspapers. Shortly before the Boer War broke out, he went to South Africa as editor of the Johannesburg Star; his opposition to the importation of Chinese labour for the Rand gold mines was so unpopular that he resigned his editorship.

In 1903, Chamberlain, together with his colleague A.S. Flemmer, applied for concessions in the East Africa Protectorate (now Kenya). They reached an agreement with Sir Charles Eliot (H.M. Commissioner in Nairobi), but this agreement was cancelled by Lord Lansdowne (Secretary of State for Foreign Affairs) and resulted in Sir Charles Eliot's resignation in Jun 1904. Chamberlain then appealed to Viscount Milner (High Commissioner for South Africa) and for the next three years he continued to press his claim with the Foreign and Colonial Offices until, in Nov 1907, Winston Churchill, as Colonial Under-Secretary, advised the Secretary of State, Lord Elgin, that the concession should be carried out in the terms arranged by Sir Charles Eliot. This advice was accepted and Chamberlain acquired 32,000 acres of land beside the Nderit Stream, which he farmed until the late 1920s, when he sold the greater part of his holding. He was largely responsible for the first wave of settlement in British East Africa (Kenya) of farmers from South Africa and also for the formation in 1911 of the Convention of Associations, a body that rendered much service to the cause of white settlers in Kenya.

Robert Chamberlain was married twice, first to Lavinia Bennet, and secondly to Janet Duncan Grant, of Dufftown, Banffshire.

Chamberlain died at Elmenteita, Kenya, in 1948.