Wong undertook pupillage with
Andrew Li, and was the latter's last ever pupil. In 1987, he was
called to both the
Bar of England & Wales and
the Bar of Hong Kong. He was appointed a
Senior Counsel in 2002. He sat as a Deputy
High Court Judge of the
Court of First Instance in July 2003, and was a Council member of the
Hong Kong Bar Association from 1989 to 1990, from 1997 to 2002 and from 2003 to 2005. He was also Chairman of the Special Committee on Legal Education of the Association from 2003 to 2005. He then served as the second
Secretary for Justice of Hong Kong between 20 October 2005 and 30 June 2012, under
Donald Tsang Yam-kuen. Since his retirement from governmental office, Wong has resumed private practice as a barrister at
Temple Chambers, with a broad civil and commercial practice. On the
Hong Kong Legislative Council oath-taking controversy, Wong described the
National People's Congress Standing Committee interpretation of the
Basic Law as a "pity" and "avoidable". He added that “from the constitutional and legal perspective, the National People’s Congress Standing Committee undoubtedly has the power to interpret every single clause of the Basic Law ... but at the same time, there is no doubt that such power must be exercised with extreme restraint and only when it is unavoidable”. When former Chief Executive
Donald Tsang was found guilty of one count of misconduct in public office in 2017, Wong personally wrote a ten-page letter of mitigation, stating that "[Tsang's] significant contributions to Hong Kong in the past over 4 decades should be properly recognized." ==Personal life==