Cheng started his career in the 1970s, where he gained a reputation for playing the lead roles in TVB Wuxia drama series based on the works of Louis Cha and Gu Long, such as The Heaven Sword and Dragon Saber and Chor Lau Heung.

He also performed some of the theme songs of the TV series he starred in, such as The Greed of Man and Cold Blood Warm Heart.

Cheng played Ting Hai (丁蟹) in the series, who made an immense fortune by short selling derivatives and stocks during a bear market.

Many people went bankrupt while Ting Hai's family became richer until they were defeated by their nemesis.

The effect involves a peculiar and unexplained phenomenon, in which global stock markets will fall whenever a new Hong Kong TV drama series, starring Cheng, is aired.