Patrick Nixon was born 1 August 1944, the son of John Moylett Gerard Nixon and Hilary Mary (née Paterson). He was educated at Downside and Magdalene College, University of Cambridge. In 1968, he married Elizabeth Rose Carlton, having four sons.

Nixon joined the Diplomatic Service in 1965, and his diplomatic career included: MECAS, Lebanon, 1966; Cairo [Egypt], 1968; Lima [Peru], 1970; Foreign and Commonwealth Office, 1973; Tripoli, Libya, 1977; British Information Services, New York [United States], 1980; Assistant, later Head, Near East and North Africa Department, FCO, 1983; Ambassador and Consul-General at Doha, Qatar, 1987–90; Head, Middle East Department and Crisis Centre, FCO, 1991–94; High Commissioner to Zambia, 1994–97; Director, FCO, 1997–98; Ambassador to United Arab Emirates, 1998–2003; Regional Coordinator for Coalition Provisional Authority, Southern Iraq, 2004.