Thomas has been active in social movements since his undergraduate study. His research interests and social participation are highly interrelated. For example, the political development of Hong Kong and labour issues under economic restructuring.
Thomas joined HKCC in 2008 as lecturer, teaching courses related to social science and political science. Before joining HKCC, he had taught for years in various tertiary education institutions on both full-time and part-time bases. The subject areas mainly focus on political science and policy studies.