Whilst known primarily for his comedic acting roles in Hong Kong cinema, he also spent time as a political activist.

He was also a student activist in the 1970s back in his youth and was a member of a Trotskyist vanguard party the Revolutionary Marxist League.

Sham is credited as a producer on over 20 films, including Hong Kong 1941 (1984), The Lunatics (1986), Legacy of Rage (1986) and The Banquet (1991).

[2] In 2005, he was appointed the Executive Secretary of the Federation of Hong Kong Filmmakers, by the government-sponsored Film Development Committee (FDC).

[4] His latest role is as executive producer, alongside Jackie Chan, for the film Wushu (2008), which was directed by Antony Szeto and starred Sammo Hung.