El-Ghassim is a conflict prevention, mediation, and peacekeeping expert with over 30 years of experience at the United Nations and African Union. He most recently served as the UN Secretary-General's Special Representative in Mali and Head of MINUSMA (2021-2023), and previously as Assistant Secretary-General for Peacekeeping Operations (2016-2017). At the African Union, he held senior roles including Director for Peace and Security and Chief of Staff to the Chairperson. El-Ghassim has also contributed to academic and policy discourse as a Visiting Professor at George Washington University, lecturer at Sciences Po Paris, and currently as a Visiting Senior Research Fellow at King's College London's African Leadership Centre. He recently led a major study on "The Future of Peacekeeping, New Models and Related Capabilities" to inform the 2025 UN Peacekeeping Ministerial in Berlin. He holds advanced degrees in international relations and international law from the Universities of Dakar and Lille II, and is fluent in French, English, and Fulani.