Patrick Costello served as an European Union official for 27 years working in the European Parliament (EP), the European Commission, and the European External Action Service (EEAS). He is currently an adviser to European Partnership for Democracy, Election-Watch EU, and the Kofi Annan Foundation.

He has served in a number of private offices including those of Chris Patten, Vice-President Margot Wallström (as deputy head of cabinet), EP President Josep Borrell (as diplomatic adviser) and Karmenu Vella (as head of cabinet).

Costello was also the EEAS head of division for democracy and electoral observation, head of division for the Middle East and deputy to the chair of the Political and Security Committee. Prior to joining the European Institutions, he worked for the United Nations in Haiti (MICIVIH) and as an electoral observer in South Africa (UNOMSA). He started his career as a human rights campaigner. Costello has recently joined the advisory board of the European Partnership for Democracy.

Costello was an event speaker at the Dialogue.