American legal scholar known for his exhaustive codification of international law. His advice on matters pertaining to international adjudication was frequently sought by the U.S. government.

Admitted to the Delaware bar in 1883, Moore in 1885 joined the U.S. Department of State, where he served until 1891. He then joined the faculty of Columbia University, retiring in 1924 as Hamilton Fish professor of international law and diplomacy. From 1912 to 1938 he was a member of the Permanent Court of Arbitration, The Hague. Among Moore's studies in international law is the monumental Digest of International Law, 8 vol. (1906). Between 1929 and 1933 he edited the eight-volume compendium of International Adjudications, Ancient and Modern.