Sir George Bailey Sansom was a diplomatist and Japanese scholar, was born in London on 28 November 1883, the only son of George William Morgan Sansom, naval architect, of Little Thurrock, Essex, and his wife, Mary Ann Bailey, from Yorkshire. He was educated at Palmer's School, Grays, and the lycée Malherbe, Caen, and later attended the universities of Giessen and Marburg. He passed a competitive examination for the British consular service in September 1903 and was attached to the British legation in Tokyo to study the Japanese language. He served as private secretary to Sir Claude Macdonald, ambassador to Japan, from 1905 to 1912, and also in consulates around Japan. In these posts, he acquired great proficiency in the Japanese language, including local dialects. In 1915 he was in London on home leave and, being unfit for military service, was lent by the Foreign Office first to the Admiralty and then to the War Office for political intelligence work, which took him to Archangel.

Sansom worked as secretary to the ambassador, Sir Charles Eliot, a post in which he made the acquaintance of many Japanese leaders and scholars. Eliot, for whom he had unbounded admiration, encouraged him to devote the spare time which was available to him in the relatively relaxed pace of official life to the study of Japan, her language, culture, and history. In 1928 he published his first work, An Historical Grammar of Japanese, a pioneer study. Already regarded as an authority on the early history of Japan, he published in 1931 Japan: a Short Cultural History, which was based on primary materials in Japanese and added a new dimension to the English-language literature on the subject. While he was dissatisfied with aspects of the work and wanted to revise it, it was reprinted as it stood in 1936 and on countless occasions thereafter. It became the standard and most reliable text for the university courses on the subject which were growing up in the United States and elsewhere. Sansom then edited the monograph Japanese Buddhism (1935) which Eliot had left incomplete at the time of his death in 1931 and added a chapter of his own. His scholarship was recognized when, during leave in 1935, he spent half a year in New York, lecturing at Columbia University.

From the 1920s Sansom was responsible for the commercial work of the embassy. He was appointed commercial secretary in September 1923 and then commercial counsellor in January 1930. In this capacity he travelled to the Philippines in 1932 and then to India in the autumn of 1933, where he played an important negotiating role in resolving the difficult Indo-Japanese cotton dispute in a dual capacity as representative of both the Indian and British governments. He was made a KCMG in June 1935, having been appointed CMG in January 1926.

From 1947 to 1953 Sansom was professor of Japanese studies at Columbia University and from 1949 to 1953 he was the first director of its East Asian Institute. It was during this period that he wrote The Western World and Japan: a Study in the Interaction of European and Asian Cultures (1950), in which he emphasized the influence of Western thought as it reached Japan down the centuries. He was able to make another academic visit to Japan in 1950 and to publish the seminal lectures he gave on that occasion under the title Japan in World History (1951). In 1955 he decided on health grounds to move to California, where he was given an honorary ‘consultant professorship’ at Stanford University. There he spent much of the last ten years of his life, freed from routine work, working on his three-volume History of Japan (1958–64). Considering the exacting standards that he set for himself, it was a marvellous publication, but the strains of age and illness affected the final volume. He had built up over half a century a range of intellectual contacts in Japan unusual for a diplomatist; and he was able to plough into his writing the richness of Japanese material towards which he was guided by a network of academic friends. He became an honorary fellow of the Japanese Academy in 1951.

Although Sansom's official career was distinguished in its own right, it is as an interpreter of Japan that he will be remembered. His writings, originating in linguistic and Buddhist studies, gradually moved away from cultural history and in later works tended towards social and political history. He was the bridge between Japanese scholars who were anxious to have their country understood abroad and a western readership who appreciated the style and wit of his writing.