George Ivan Smith (1915-95) was born in Sydney, Australia, the son of George Franklin Smith, a prison governor, and May Sullivan. After education at Bathurst and Goulburn High Schools and at Sydney University, Smith began work as a newspaper journalist. In 1937 he joined the Australian Broadcasting Commission as talks editor and in 1939 became director of the newly-founded overseas broadcasting service, Radio Australia. In 1941 Smith was seconded to the BBC's Overseas Service in London where he became head of the Pacific Service and organised overseas coverage of the Second Front. In 1945 he joined the J. Arthur Rank Organisation where he worked on the documentary series 'This Modern Age'.

Smith joined the United Nations in 1947 and went to New York as Director of External Affairs to establish the organisation's first international radio programmes. In 1949 he moved to a more political role when he came to Britain as first director of the London United Nations Information Centre, remaining there until 1958. He began to act frequently as spokesman for Dag Hammarskjold, who had become Secretary-General in 1953, and accompanied him on many missions, including his visit to the Middle East following the Suez crisis. He was in charge of press liaison at the Four Powers' summit conference and foreign ministers' meeting in Geneva in 1955. In 1958 Smith returned to New York, firstly as Director of the External Relations Division of the UN Office of Public Information and later as Director of Press and Publications.

Smith's close association with Africa began in 1960-1 when he undertook several missions to the Congo and served as chief of civilian operations in Katanga in the wake of Hammarskjold's death in an air crash in September 1961. The following year he was appointed regional representative of the UN Technical Assistance Board (UNTAB) in East Africa and personal representative of the new Secretary-General, U Thant, in East, Central and Southern Africa. Based initially in Dar es Salaam and, from January 1964, in Lusaka, Smith negotiated with the colonial governments and the emerging African leaders.

In 1965 Smith took a sabbatical from the United Nations and became visiting lecturer in international affairs at the Woodrow Wilson School of Public and International Affairs at Princeton University and the following year a visiting professor at the Fletcher School of Law and Diplomacy in Boston. In 1967 he undertook four months work for the World Security Trust on the problems of nuclear proliferation and acted as consultant to various international corporations. In 1965 he was nominated for the new post of Secretary-General of the Commonwealth but the appointment went to his namesake Arnold Smith of Canada.

In 1968 Smith was again appointed director of the London Information Centre where he remained until his retirement from the United Nations in 1975. From his home in Gloucestershire he continued to be an active commentator on international affairs and supporter of the United Nations, travelling, lecturing, and writing articles, letters to the press and a book, Ghosts of Kampala (London, 1980), about the rise and fall of Idi Amin. He began work on other books, notably an autobiography and an account of his pioneering ancestors in early Australia, but did not complete them, mainly because he was caring for his wife, who was in poor health.

In 1938 Smith married Madeleine Oakes (1909-66) in Sydney and they had three children. The marriage broke up during the war. In 1944 he married Mary Douglass (b.1909) who had two daughters from her first marriage to Cyril Conner (1900-81), the writer Penelope Gilliatt (1932-93) and the sculptor Angela Conner (b.1935?). In 1964 the Smiths adopted Edda Mutzawelo (b.1960).