Griffiths previously served as the first executive director of the European Institute of Peace from 2016 to September 2018.[8] In 1999, he helped launch the Centre for Humanitarian Dialogue in Geneva.[9] On 12 May 2021, United Nations Secretary-General António Guterres announced that he had appointed Griffiths as Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator, Office for the Coordination of Humanitarian Affairs (OCHA).[10]