Professor Leong is presently President of the Open University of Hong Kong, and Emeritus Professor of the University of Hong Kong. He is also Honorary Professor of Departments of Biochemistry and Orthopaedics & Traumatology of the same University. He was appointed Justice of the Peace in 1981, and OBE (Officer of the Most Excellent Order of the British Empire) in 1996.

He was born in Hong Kong in 1942, and received his primary and secondary education at St. Joseph's College, Hong Kong. He graduated Bachelor of Medicine and Bachelor of Surgery at the University of Hong Kong and became Fellow of the Royal College of Surgeons of Edinburgh (1969), and Fellow of the Royal College of Surgeons of England (1970) by examination. He was admitted as Fellow of the Royal Australasian College of Surgeons (1985), and Fellow of the Hong Kong Academy of Medicine (1993) without examination. He was conferred an Honorary Fellowship by the Royal College of Orthopaedic Surgeons of Thailand in 2001.

Before joining the Open University of Hong Kong, Professor Leong had been working in his alma mater, The University of Hong Kong, for 38 years. He was Chair Professor and Head of the Department of Orthopaedic Surgery from 1981 to 2003. Concomitantly, he headed the Department of Orthopaedics and Traumatology at Queen Mary Hospital. He was Dean of the Faculty of Medicine from 1985 to 1990, and Director of the School of Postgraduate Medical Education and Training, Faculty of Medicine, from 1993 to 1999.

Professor Leong is an internationally renowned clinician-scientist specializing in spinal and pediatric orthopaedics. He has published more than 200 full papers in the top journals in orthopaedic surgery, and 36 invited chapters/articles in books/journals. He was President of the Société Internationale de Chirurgie Orthopedique et de Traumatologie (SICOT) from 2002-2005, the world orthopaedic association with 105 member nations established in 1929 in Paris, and incorporated in Brussels. He is the first Chinese to head the association. In 2001, Professor Leong was elected an Academician of the Chinese Academy of Science, the first clinician in Hong Kong to receive the honour.

He has been Institution-Sponsored Guest Speaker / Endowed Visiting Professor more than 200 times in many distinguished institutions worldwide, including as C. Howard Hatcher Visiting Professor at Stanford University, Keynote Speaker at the Imperial College of the University of London, Greg Houghton Memorial Lecturer of the British Scoliosis Society, Dewar Spinal Visiting Professor at the University of Toronto, F.P. Patterson Visiting Professor at the University of British Columbia, and Francoise P. Fouche Lecturer of the Colleges of Medicine of South Africa.

He is an honorary member of the Orthopaedic Societies of Argentina, Cuba, Portugal and Western USA; honorary member of the British Scoliosis Society, and ARGOS. He is an invited member of the American Orthopaedic Association, Spine Society of Australia, the International Orthopaedic Association, and the Japanese Orthopaedic Association.

He has also been appointed Honorary Professor at the Sun Yat-Sen University of Medical Sciences, Norman Bethune Medical University, West China University of Medical Sciences, First Military Medical University, Peking Union Medical College Hospital, Tianjin University, Sichuan University, and Hainan University

Professor Leong was Chairman of the Hong Kong Council for Academic Accreditation from 1999 to 2003 and Chairman of the Joint Committee on Student Finance of the Hong Kong Government from 1992 to 1999. He is Chairman of the Hospital Governing Committee of Castle Peak Hospital, and Chairman of the Committee on Libraries (Hong Kong Public Libraries). He is also a member of the International Commission of the Council for Higher Education Accreditation in the United States, and International Network of Quality Assurance Agencies in Higher Education. Recently he has been appointed Chairman of the Licentiate Committee of the Medical Council of Hong Kong, Member of the Operations Review Committee of the Independent Commission Against Corruption and its Witness Protection Review Board Panel, and Member of the Statistics Advisory Board.