After graduation, he joined the Hong Kong Government as executive officer and subsequently left the civil service for academia in 2007.

[2][3] After obtaining his doctoral degree, Fong joined the Department of Asian and Policy Studies of the Education University of Hong Kong in 2013 as assistant professor.

[4] In August 2022, Fong took up the position of Professor in the College of Social Sciences at National Sun Yat-sen University, Taiwan.

Fong focuses on studying Hong Kong's governance and constitutional reform, and he keeps participating in related advocacies.

[11] Fong was once appointed to several government boards and committees in Hong Kong, including Part-time Member of Central Policy Unit of HKSAR Government (From January 2011 to December 2012) and Member of Subsidised Housing Committee of Housing Authority (From April 2014 to April 2018).