Born in 1949 in Hong Kong, Dennis Chan Kwok-sun is the younger brother of actor-director Philip Chan. While still in school, Chan appeared with his band on a television variety show and was invited by a RTHK director to audition. He was accepted and performed regularly in TV dramas in the 1970s. In 1977, he became producer for variety shows. He first acted in film in Cop and Robbers (1979), followed by over 90 films, mostly in cameos. He starred in Krazy Kops (1981) and Romantic Fool (2007) and played major parts in Soul (1986), Cageman (1992) and the American film Kickboxer (1989) and its two sequels.
Chan joined D&B in 1984 as Distribution Manager, leaving in 1987 to learn film production at Hollywood. Returning to the Hong Kong film industry, he worked primarily in producing, writing and directing. Films he produced or associate produced include The Wrong Couples (1987), Hearts to Hearts (1988), Naked Killer (1992) and Future Cops (1993). Chan often doubled as writer on films he produced, such as Remains of a Woman (1993), which was awarded Best Actress (for Carrie Ng) at the Golden Horse Awards, and Wild Horse from Shangri-La (2009).
Chan directed his first film, Perfect Match, in 1989, a year in which he also released a second film, Maybe Next Time. He also directed the romance drama Love and Let Love (1998). In 1993, he became COO of Vehicle Of Light Film Company and in 1999, ran the China Culture Media Group Company, which produced programs on Chinese history and culture.
Chan resumed film production in 2006, such as producing and writing Air Diary (2006), Wild Horse from Shangri-La (2007), Besieged City (2008) and directing The Romantic Fool (2007, which Chan also wrote), Wushu: The Young Generation (also co-wrote, 2008, co-director, Anthony Szeto) and 37 (2009).