Mr Tsang was admitted as a solicitor in Hong Kong in 1992 and in the United Kingdom in 1995. He was appointed Government Counsel in 1998 and promoted to Senior Government Counsel in 2001, Deputy Principal Government Counsel in 2007, Principal Government Counsel in 2012, and Law Officer in 2017. Mr Tsang has served in different divisions of the department for 20 years and has rich experience in advising the Hong Kong SAR Government on the negotiations of Free Trade Agreements and Investment Promotion and Protection Agreements as well as complex litigation and dispute settlement actions involving public international law.