Before finishing his school he signed a contract with Kin Shing Film Company, but it wasn't until the mid-70s he becomes popular thanks to TV Series "Book and Sword" (1976), "Heavenly Sword and Dragon Sabre" and "Fragrant Hero Chor Lau Heung" (both from 1979). Cheng himself performed their theme songs, so also became a popular singer. After a successful film career in Hong Kong in the 80s, he finally returned to TV.