He earned his B.A. and M.A. degrees in Political Science from the American University of Beirut. His educational qualifications and professional achievements entitled him to earn the Fulbright scholarship to pursue graduate studies in the US focusing on Conflict Transformation and Peacebuilding. Fadi also obtained mediation and negotiation training from Harvard University, UN System Staff College and the United States Institute of Peace.
El Hajjar assumed leadership and managerial roles to provide technical support in the areas of peacebuilding and conflict prevention. Recently he led the peace portfolio with UNDP in Sudan. In 2018, he developed the peacebuilding plan for different UN interventions in South Sudan. In 2014, Fadi co-designed and implemented the Cordaid flagship research project which focused on the role of civil society in economic development, peacebuilding and state building in different countries across the globe. Until October 2012, Fadi was with UNDP Lebanon as the Project Manager for the "Strengthening Civil Peace" project. Moreover, he contributed to national dialogue processes in fragile multi-party contexts such as Lebanon, Libya, Sudan, Iraq, Syria and Yemen. In the US, El Hajjar worked at the Carter Center on conflicts taking place in Somalia, Eritrea, Ethiopia and Sudan during which he developed the memo of intervention which President Carter used to mediate in the Darfur crisis. He also worked on a project related to religion and conflict, particularly on the means of negotiating with fundamentalists.
El Hajjar has been a panel speaker and lecturer in many conferences in different countries. He also conducted workshops and was a facilitator in reputable organizations including the UN headquarters.
Being a senior political analyst and international conflict resolution expert, he has been hosted as a television and radio commentator. He also published several articles in reputable newspapers analyzing local, regional, and international political issues.
Based on his advisory capacity and expertise in political analysis, democratization, conflict resolution and development. His support has sought by reputable organizations in the MENA region and leading international organizations including the UN, Swiss Development Cooperation, FCO, USAID and the EU, conducting a variety of interventions in both Arabic and English.