Daniel J. Costello (B.A. Honours, Political Science, McGill University, 1984; M.A. Philosophy, University of Massachusetts-Amherst, 1991; Ph.D. Philosophy, University of Massachusetts-Amherst, 1995) taught for several years at the University of Massachusetts-Amherst and l'Université François-Rabelais in Tours, France, before returning to Canada to serve as Policy Adviser and Executive Assistant to the Director of Policy and Research in the Office of the Prime Minister (1996-99), Executive Assistant to the Minister of Citizenship and Immigration (1999-2002) and Chief of Staff to the Minister of Foreign Affairs (2002-2004).
He returned to teaching at the University of Ottawa in the fall of 2004 prior to joining Foreign Affairs Canada in 2005, where he has served as Director General for Intergovernmental Relations and Domestic Outreach (2005-06), Director General for the European Union and Western Europe (2006-08), Ambassador to the Republic of Poland with concurrent responsibility for Belarus (2009-12), Director General for Strategic Policy (2012-13), Associate Assistant Deputy Minister for Global Issues, Strategic Policy, Europe and the Middle East (2013) and most recently as Assistant Deputy Minister for Europe, Middle East and Maghreb (2013-15) in the newly amalgamated Foreign Affairs, Trade and Development Canada.
Ambassador Costello presented his credentials to the President of the European Council, Donald Tusk, on 29 October 2015.