Hassan is President of TWAS and of the Sudanese National Academy of Sciences; and Chair of the Governing Council of the United Nations Technology Bank for the Least Developed Countries, and of the International Advisory Board of the Centre for Development Research, Germany. He covered many high-level positions, such as President of the InterAcademy Partnership (IAP); founding Executive Director of TWAS; President of the African Academy of Sciences; founding President of the Network of African Science Academies, and Chair of the Council of United Nations University. After obtaining his PhD in mathematics from the University of Oxford, he returned to the Sudan and later became Professor and Dean of the Faculty of Mathematical Sciences at Khartoum University. Among his honours are: Comendador and Grand Cross of the Brazilian Order of the National Scientific Merit, and Officer of the Order of Merit of Italy. He is a member of several scientific academies, including the Belgian, Colombian, Cuban, Moroccan, Pakistani, South African and the Pontifical. He is the recipient of the G77 Leadership Award and of the Abdus Salam Medal for Science and Technology.