 A the Democratic Alliance for the Betterment and Progress of Hong Kong (DAB) member, he made an upset in the 2018 Legislative Council by-election in Kowloon West, being the first pro-Beijing candidate to defeat a pro-democracy opponent in an open by-election since 1992.Cheng was a son of the former Po Leung Kuk chairman Eric Cheng Kam-chung who is also a clothing retailing and computer accessories retailing businessman.He was raised in Nam Shan Estate before his father became rich.