Law first appeared in He Has Taken Him for Another, a 1957 Mandarin Comedy film directed by Li Han-Hsiang.
Law also appeared in The Lady of Mystery, a 1957 Mandarin thriller film directed by Wa Hak-Ngai.
In the 1970s, John began working under the renowned Hong Kong film studios, Shaw Studio, responsible for producing many of Hong Kong's classic martial arts film during this period.
In 1976 John directed and wrote the script for The Girlie Bar, an adult film oriented drama featuring Chan Ping, Yau Fung, Lin Chen Chi and James Nam and Tony Liu.
His 1977 romance film Orchid In The Rain, which also starred frequent star in his films, Alan Tang, Brigitte Lin also pushed boundaries in terms of intimacy on screen.