U.S. attorney and authority on international law who was an early advocate of vesting all military power in an international security organization.

Hyde taught at the law school of Northwestern University, Chicago (1907–25), and then became professor of international law and diplomacy at Columbia University (1925–45). He served as solicitor for the U.S. Department of State (1923–25) and was a member of the Permanent Court of Arbitration, The Hague (1951–52). In private practice he represented several governments. His best known publication is International Law, Chiefly as Interpreted and Applied by the United States, 2 vol. (1922; 2nd rev. ed., 3 vol., 1945).