In 1880, Buxton became prominent in political circles by the publication of his Handbook to the Political Questions of the Day, a work which eventually went through 11 editions. That same year, he ran for Parliament for Boston, but lost. However, he became an MP in 1883 by winning a by-election in Peterborough. He was defeated in the 1885 general election, but returned to Parliament the very next year, representing Poplar. He would represent this constituency in Parliament until 1914. From 1892–95, Buxton served as Under-Secretary of State for the Colonies. In 1905, he earned his first Cabinet post, that of Postmaster-General. In this capacity he introduced such services as penny postage to the United States, the Canadian magazine post, and cheap postage for the blind. In 1910, Buxton was named President of the Board of Trade; in this position he oversaw the passage or amendment of many trade and commerce laws. Upon the sinking of the RMS Titanic in 1912, he asked Lord Loreburn, the Lord Chancellor, to appoint a commission of inquiry into the disaster. This commission eventually came to be headed by Lord Mersey. In February 1914, Buxton was appointed Governor-General of South Africa, and on 11 May of that year he was raised to the peerage as Viscount Buxton, of Newtimber in the County of Sussex. A revolt by some of the South African populace on the outbreak of the First World War temporarily threatened his safety, but the country's Prime Minister, General Louis Botha, immediately attached the Union of South Africa to Britain. Thereafter, Lord Buxton and General Botha formed an effective partnership, planning and executing South African actions in the war, including the invasion of the neighbouring German colony of South West Africa. Lord Buxton travelled widely throughout South Africa, and endeared himself to the people. Upon his retirement in 1920, the people demonstrated their affection for him. He continued his interest in South African affairs after returning to England, serving as president of the African Society from 1920–33. He was created Earl Buxton on 8 November 1920, and continued to be a member of the Liberal Party, often supporting his close friend and colleague Sir Edward Grey. In his later years, he had to undergo amputation of his leg due to a knee injury sustained earlier in his life. He died at Newtimber on 15 October 1934.
Lady Doreen Maria Josepha Sydney Buxton, a fraternal twin; married 24 January 1918 Charles Alfred Euston Fitzroy, a scion of the Dukes of Grafton. She died aged 25, shortly after the birth of her third child. After her death, her husband remarried. His second wife, Lucy Eleanor Barnes, was a first cousin of his first wife through her Buxton mother, in 1924. Twice widowed, he married, thirdly, in 1944. He succeeded to the dukedom in August 1936 when a young cousin, The 9th Duke of Grafton, was killed in a motoring race.
Denis Bertram Sydney Buxton, a fraternal twin; killed in action, aged 19, Passchendaele, as a Second Lieutenant in the Coldstream Guards. At the time of his death, he was his father's only surviving son and heir to his titles. The location of his grave is unknown and he is commemorated on Panel Nine of the Tyne Cot Cemetery, a memorial bearing the names of some 35,000 men of the British and New Zealand forces who have no known grave, nearly all of whom died between August 1917 and November 1918.
Lady Alethea Constance Dorothy Sydney Buxton ; married Venerable Peter Charles Eliot, TD, MBE, son of Edward Granville Eliot and Clare Louise Phelips, on 12 July 1934. They had no issue, and Lady Alethea died aged 93 in 2004.
Since all his sons died unmarried in his lifetime, his titles became extinct at his death. Earl Buxton was survived by his second wife Mildred and his youngest daughter Lady Althea Eliot, and by eight grandchildren including the future Duke of Grafton.
Works
Handbook to Political Questions of the Day.
Mr. Gladstone's Irish Bills.
Finance and Politics: An Historical Study, 1783–1885. Volume I and Volume II.