William Fullerton was born 11 Feb 1939, son of Major Arthur Hugh Theodore Francis Fullerton, RAMC, and of Mary (née Parker). He was educated at Cheltenham College and Queens’ College, University of Cambridge (taking an MA in Oriental Languages). In 1968, he married Arlene Jacobowitz, having one daughter.

After a spell with Shell International Petroleum Company in Uganda, 1963-65, Fullerton joined the Foreign Office in 1965, and his career included the following; MECAS, Shemlan, Lebanon, 1965-66; Information Officer, Jeddah [Saudi Arabia], 1966-67; UK Mission to United Nations, New York [United States], 1967; Foreign and Commonwealth Office, 1968-70; Head of Chancery, Kingston, Jamaica (also accredited to Haiti), 1970-73; Ankara [Turkey], 1973-77; FCO, 1977-80; Counsellor (Economic and Commercial), 1980-83 and Consul-General, 1981-83, Islamabad [Pakistan]; Ambassador to Somalia, 1983-87; on loan to MoD, 1987-88; Governor of the Falkland Islands, and Commissioner for South Georgia and South Sandwich Islands, 1988-92; High Commissioner, British Antarctic Territory, 1988-89; Ambassador to Kuwait, 1992-96; Ambassador to Morocco and Mauritania, 1996-99.