Mr Lee joined the Civil Service in June 1990. He first served as an Executive Officer and then transferred to the Administrative Service. He rose to the rank of Administrative Officer Staff Grade B1 in April 2022. He has served in various bureaux and departments, including the former City and New Territories Administration, the former Planning, Environment and Lands Branch, the Department of Health, the former Civil Service Branch, the former Industry Department, the former Education and Manpower Bureau, the Hong Kong Economic and Trade Office in Geneva, the former Constitutional Affairs Bureau, the Home Affairs Department and the Hong Kong Economic and Trade Office in Berlin. He was Deputy Director of Housing from September 2014 to January 2018, Deputy Commissioner for Innovation and Technology from January 2018 to December 2020, and Commissioner for Efficiency from December 2020 to June 2023. Mr. Lee was appointed as Commissioner for Innovation and Technology on 12 June 2023.