Before joining the Government, Mr Lam was a Senior Counsel in private practice specialising in general civil and commercial proceedings, and has passed the Guangdong-Hong Kong-Macao Greater Bay Area Legal Professional Examination. He was a former Vice-Chairman of the Hong Kong Bar Association from 2014 to 2017 and the Chairman from 2017 to 2018. He sat as a Deputy Judge of the High Court of Hong Kong for short periods each year since 2015. He was once enlisted in the Panel of Arbitrators of the Shenzhen Court of International Arbitration and The China International Economic and Trade Arbitration Commission, and was once appointed by the China University of Political Science and Law in Beijing as professor.
Mr Lam held a number of public service positions, such as Chairman of the Consumer Council, Chairman of the Administrative Appeals Board, Chairman of ICAC Operations Review Committee and Member of Independent Police Complaints Council.