Arthur Augustus William Harry Ponsonby, 1st Baron Ponsonby of Shulbrede, was born on February 16, 1871, at Windsor Castle, Berkshire, England, son of Sir Henry Ponsonby (1825-1895), Private Secretary to Queen Victoria.

He was a British politician, writer, and social activist. He was a Page of Honour to Queen Victoria from 1882 to 1887. He was educated at Eton College and Balliol College, Oxford (1890-1892). In 1894, he went abroad to learn German and French and entered the diplomatic service. Following service in Constantinople and Copenhagen, he moved to the Foreign Office in 1900 but resigned in 1902 to further a career in politics. He served first in the Liberal Central Association office and, then in 1906, he was appointed principal private secretary to the prime minister, Campbell-Bannerman. He joined the Labour Party and returned to the House of Commons at the 1922 general election as a member of the Brightside division of Sheffield. In 1924, Ponsonby was appointed as Parliamentary Under-Secretary of State for Foreign Affairs, then Under-Secretary of State for Dominion Affairs, and as Parliamentary Secretary to the Ministry of Transport (1929-1931). In 1930, he was raised to the peerage as a hereditary baron. He also served as Chancellor of the Duchy of Lancaster in 1931. Ponsonby served as Leader of the Labour Party in the House of Lords (1931-1935) but resigned because he was opposed to the party's support for sanctions against Italy for its invasion of Abyssinia. He published his father's biography "Henry Ponsonby, Queen Victoria's Private Secretary: His Life and Letters" (1942), which won the prestigious James Tait Black memorial prize.

In 1898, he married Dorothea Parry (1876–1963). He died on March 23, 1946, in Hindhead, Surrey, England.