Hui is the son of a veteran pro-Beijinger Hui Wang-chuen who is a leader of one of the major Fujian associations in Hong Kong. His sister, Florence Hui, was an Under Secretary for Home Affairs. His wife, Rita Chan, is an executive director at Goldman Sachs (Asia).
Hui received his bachelor's degree from the University of Oxford, and his Master of Business Administration from the INSEAD graduate business school. In 1999, he was admitted as an Administrative Officer in the Government and served in the Economic Development Branch, the Office of the Government of the Hong Kong Special Administrative Region in Beijing and the Home Affairs Department until 2003.
After he left the government in 2003, Hui worked in the banking sector and became a managing director at Hong Kong Exchanges and Clearing for 12 years. He was also as a director of strategic development at New World Development, which was responsible for the development of the Greater Bay Area, the national plan to integrate Hong Kong with Macau, and other nine Guangdong cities, as a financial and technological powerhouse.
In 2008, he joined the Democratic Alliance for the Betterment and Progress of Hong Kong (DAB), the largest pro-Beijing party in Hong Kong, and has served on its standing committee. In 2014, he was appointed by Chief Executive Leung Chun-ying as a council member of City University of Hong Kong. In 2019, Hui was appointed executive director of the Hong Kong Financial Services Development Council.
In April 2020, Chief Executive Carrie Lam appointed Hui Secretary for Financial Services and the Treasury, one of the principal officials of the Hong Kong government, even as he remained a member of the DAB.
- "New faces Carrie Lam has enlisted to help Hong Kong tackle coronavirus impact". South China Morning Post. 20 April 2020.
- "Government announces appointment and removal of Principal Officials (with photos)". Hong Kong Government. 20 April 2020.
| Secretary for Financial Services and the Treasury