Sham grew up in a single-parent family and completed secondary school in 2006. He worked as a legislative assistant for a period after graduating from secondary school. He later joined Rainbow Action, a member organisation of Civil Human Rights Front that advocates for LGBT rights. He started assisting with CHRF's work in 2008, hosting events and managing affairs with human and police rights. He occupied Connaught Road Central along with other protesters after the 1July march in 2011, after which he was arrested for unlawful assembly. He participated in the 2014 Hong Kong protests and became CHRF's convener in 2015, for one year.