Prof Leong received the B.Sc. (Hon) in Mathematics from University of Malaya and Ph.D. degree in Computer Science from the University of Illinois at Urbana-Champaign.
His research interests are in the design and analysis of algorithms, optimization and discrete mathematics. He works in many areas including VLSI design, transportation logistics, multimedia systems, and computational biology.
In Singapore, he started the Singapore training program for the IOI (International Olympiad in Informatics). He is a member of ACM, IEEE, ISCB, and a Fellow of the Singapore Computer Society.