O'Hara was born on 11 June 1964 in Dublin, Ireland.[1] He graduated with a Bachelor's degree in legal science from Trinity College Dublin and later received a barrister at law degree from Kings Inns.[5]
From 2012 to 2016 he was the Irish ambassador to Ethiopia.[5] During his time as ambassador to Ethiopia, he helped facilitate money for the assistance of Ethiopian migrants returning from Saudi Arabia.[6] He was replaced by Sonja Hyland in this post, who also took on the missions of Djibouti, South Sudan, and the African Union.[7] Following his tenure as ambassador, he served as Director of Policy Planning at the Department of Foreign Affairs and also as Director of the European Division[5] From 2019 to 2022 he was the Ambassador of the European Union to Djibouti and the Intergovernmental Authority on Development.[5] He announced during his term that he wanted to strengthen cooperation projects between the EU and Djibouti like those on child development and equality for women in the country.[8]
Since 2022 he has been the European Union's Ambassador to Sudan.[3] On 17 April 2023, he was reportedly assaulted at his home in Khartoum amid the ongoing civil conflict and battle over the city.[9] He later explained that the group who attacked him were searching for cash and mobile phones. Although he wasn't injured in the initial incident, he was attacked again during his evacuation through a Sudanese airbase, during which a member of his convoy was wounded.
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