Dr Cheng is a practising solicitor.  He is currently a senior consultant of Messrs P C Woo & Co, one of the longest established firms of solicitors in Hong Kong; after serving as its senior partner for 22 years.  Besides, Dr Cheng is also a Notary Public, a China-Appointed Attesting Officer and an independent non-executive director of several companies whose shares are listed on the Hong Kong Stock Exchange.

Currently Dr Cheng is a non-official member of the Executive Council of the Hong Kong Special Administrative Region.  He is also Chairman of the Council of the Hang Seng University of Hong Kong, Council of the St Paul’s Co-educational College, the Ma Wan Park Advisory Committee, the Chancellor of the Hong Kong Sheng Kung Hui (the Anglican Church of Hong Kong) and a member of the Vestry of the SKH St Paul’s Church.  

Dr Cheng was the founder Chairman of the Insurance Authority, Opera Hong Kong and the Hong Kong Institute of Directors of which he is now the Honorary President and Chairman Emeritus.  He had also served as a member of the Legislative Council and the Financial Leaders Forum.  Dr Cheng also served previously as Chairman of, among others, the Board of Education, the Education Commission, Free Kindergarten Education Committee, the Council of the Hong Kong Baptist University as well as a district governor of Rotary International District 3450.  

Dr Cheng was also a member of the National Committee, the Beijing Committee and the Chengdu Committee of the Chinese People’s Political Consultative Conference of the People’s Republic of China.  He was awarded by the HKSAR Government the Justice of the Peace in 1996, the Gold Bauhinia Star in 2003 and the Grand Bauhinia Medal in 2016.