Prior to his legal career, Koon-yiu gained over a decade of professional experience as an academic researcher, public administrator and technology consultant with the University of Cambridge, the Hong Kong Innovation & Technology Commission and the Hong Kong Productivity Council.
Koon-yiu has a Ph.D. in Microelectronic Engineering & Semiconductor Physics from the University of Cambridge and a B.Sc. (1st Class Honours) in Physics from Imperial College London. He received his JD and PCLL from the University of Hong Kong.