In 1973, Bruce Lee offered Liu a role in the movie named The Game of Death as a villain, but John Liu respectfully refused.
Tan Tao Liang thought John Liu's flexibility was so poor, he made him do the splits by resting each foot on two piles of bricks. According to Tan Tao Liang, it took John Liu two years of excruciating stretching to achieve the splits.
John Liu is the creator of the martial art known as Zen Kwan Do. He founded the first Zen Kwan Do school in Paris.