 He became a judge of the Supreme Court of Hong Kong in 1991 and was appointed to the Court of Appeal in 1997.The Supreme Court of Hong Kong was renamed the High Court of Hong Kong when Hong Kong was returned to China on 1 July 1997.Leong was due to retire in 2000, but was appointed Chief Judge of the High Court of Hong Kong in that year and had his term of office extended for 2 and a half years.