Sir Julian King is a British diplomat and civil servant with more than 30 years of experience working on international and multilateral issues across the United Kingdom, the United States, and Europe. He joined the Foreign and Commonwealth Office in 1985 and went on to hold senior postings in Brussels, New York, Paris, Luxembourg, The Hague, Lisbon, and London, including roles as British Ambassador to Ireland and British Ambassador to France.

Sir Julian served as the United Kingdom's European Commissioner from 2016 to 2019, holding the newly created Security Union portfolio under European Commission President Jean-Claude Juncker. His appointment was confirmed by the European Parliament and the Council of the European Union, and he became the final British official to hold a position within the European Commission following the UK's withdrawal from the EU.

Sir Julian was appointed Companion of the Order of St Michael and St George in 2006 and Commander of the Royal Victorian Order in 2011. He holds a Bachelor of Arts in Philosophy and Theology from St Peter's College, Oxford, and studied at the École nationale d'administration in Paris.