British statesman and philosopher, one of the first Jewish members of the British cabinet (as chancellor of the duchy of Lancaster, 1909–10). He was perhaps most important as first British high commissioner for Palestine (1920–25), carrying out that delicate assignment with varying but considerable success.

Samuel was a social worker in the Whitechapel slum district of East London when elected to the House of Commons as a Liberal in 1902. As parliamentary undersecretary to the Home Office (1905–09), he was responsible for legislation (1908) that established juvenile courts and the “Borstal” system of detention and training for youthful offenders. Twice postmaster general (1910–14, 1915–16), he recognized the postal trade unions and nationalized the telephone services. In January 1916 he became home secretary in Herbert H. Asquith's coalition ministry, but he resigned in December when David Lloyd George formed his coalition government.

Although his five-year administration in Palestine was occasionally disturbed by turmoil brought about by both Jewish and Arab nationalist dissension, Samuel greatly improved the economy of the region and strove for harmony among the religious communities. Returning to Great Britain, he presided (1925–26) over the royal commission on the coal industry and helped to settle the general strike of May 1926. Reentering the House of Commons in 1929, he joined Ramsay MacDonald's national coalition government in 1931 as home secretary, but, as a confirmed free trader, he resigned in September 1932 in protest against import tariffs. He was leader of the Liberal Party from 1931 to 1935, but his actions widened the division within the Liberal Party, which ceased to be an important factor in national elections. Created viscount in 1937, he led the Liberals in the House of Lords (1944–55).

As president (1931–59) of the British (later Royal) Institute of Philosophy, Samuel interpreted philosophy to the public in such books as Practical Ethics (1935) and Belief and Action (1937; new ed. 1953).