Mr Mok has been a practising barrister in Hong Kong for over 24 years; he was appointed Senior Counsel in 2006. Mr Mok was a Member of the Consumer Council, a Member of the Air Transport Licensing Authority and a Part-time Member of the Central Policy Unit. He is currently a Member of the Committee for the Basic Law of the HKSAR under the Standing Committee of the National People's Congress. Mr Mok focuses on cases with a public dimension, which include public inquiries, applications for judicial review, regulatory and administrative hearings and appeals. Mr Mok also regularly represents and advises the Government in fields ranging from constitutional and administrative law to policy and other civil matters. Mr Mok was the Leading Counsel representing the Chief Executive in the election petition lodged in respect of the 2012 Chief Executive Election.