[5] Neville-Jones was a career member of Her Majesty's Diplomatic Service from 1963 to 1996, during which time she served in British Missions in Rhodesia, Singapore, Washington, DC and Bonn.

From 1994, until her retirement, she was Political Director in the Foreign and Commonwealth Office, in which capacity she led the British delegation to the Dayton negotiations on the Bosnia peace settlement.

[8] In 1996, shortly after resigning from the Foreign Office, Neville-Jones and her former boss Douglas Hurd were hired by NatWest Markets, a British bank, to travel to Belgrade and negotiate a privatisation deal with Slobodan Milosevic for Serbia's state telecoms industry.

From 2002 to 2005, Neville-Jones was non-executive chairman of the part Government-owned defence technology company QinetiQ, which was privatised for £1.3 billion in February 2006.

[14] On 13 May 2010, she was appointed Minister of State for Security and Counter Terrorism in David Cameron's Conservative–Liberal Democrat coalition government, and was also sworn of the Privy Council.

[15] Neville-Jones later spoke out against "internet hate preaching and jihadist rhetoric", arguing that the murder of Lee Rigby was likely to have been inspired by such material.

She wrote about the quantum technology revolution and related that the "policy failure" of the 2003 Iraq War was due to "outdated intelligence, lack of ability to test agent information against other sources and misinterpretation of apparent battlefield evidence".