John Rankin was born 12 March 1957, the son of James Rankin, CBE, and Agnes Rankin (née Stobie). He was educated at Hutchesons’ Boys’ Grammar School and the University of Glasgow (LLB 1st Cl. Hons), before studying at McGill University, Montreal (LLM with distinction). In 1987, he married Lesley Marshall (they were divorced in 2019), having one son and two daughters.

After beginning his career as a solicitor and Member of the Law Society of Scotland, Rankin spent four years as a Lecturer in Public Law at the University of Aberdeen, 1984–88. He then joined the Foreign and Commonwealth Office, and his diplomatic career included: Assistant, then Senior Assistant Legal Adviser, 1988–90; Legal Adviser, UKMIS and UKDIS, Geneva, 1991–94; Legal Counsellor, FCO, 1994-96; Deputy Head, OSCE Department, 1996–98; Counsellor and Deputy Head of Mission, Dublin [Ireland], 1999–2003; Consul General, Boston [United States], 2003–07; Assistant Director, Human Resources, FCO, 2007-09; Director, Americas, FCO, 2009–11; High Commissioner to Sri Lanka and (non-resident) to the Maldives, 2011–15; Chargé d’Affaires, Nepal, 2015; Governor and Commander-in-Chief of Bermuda, 2016–20; Governor, British Virgin Islands, 2021–23.