香港專上學生聯會
Shum was elected vice president of the Student Union at CUHK and held the position from 2013 to 2014. He then served as deputy secretary-general of the Hong Kong Federation of Students (HKFS), from April 2014 to March 2015. In his role, Shum and student leader Alex Chow galvanized the 2014 class boycott campaign against the decision of the National People's Congress Standing Committee (NPCSC), which set the framework of the restrictive electoral method in the 2017 Chief Executive election.