Before he was appointed as Ambassador, Jernegan worked as the Director of the Office of Greek, Turkish and Iranian Affairs (1949-1950) and Deputy Assistant Secretary for Near Eastern, South Asian and African Affairs (1952-1955).[3] Jernegan also held the position of Faculty Advisor at the Air University at Maxwell Air Force Base.[3]
He was considered Persona non Grata after siding with Britain when Britain planned to protect Kuwait when Abdul Karim Qasim, the Iraqi leader, laid claim to Kuwait.[4][5] Qasim “designated the Kuwaiti monarch “qa’im maqam” – a subordinate to the governor of Basra – and threatened to “liberate” the country by force if the Kuwaiti monarch refused to accept this new designation.” .[6]
^"California Death Index, 1940-1997," database, FamilySearch 26 November 2014, John Durnford Jernegan, 06 Nov 1980; Department of Public Health Services, Sacramento.