Thomas was born and raised in Hong Kong. His family had walked faithfully with Jesus for three generations. He came to Canada for Medical School at the University of Manitoba in 1970. After practicing as a Family Doctor for 17 years, he entered postgraduate training in Psychiatry at the University of Toronto. He practised in adult psychiatry, sub-specializing in schizophrenia, being an active staff at the Scarborough Hospital, till his retirement in June 2015. Thomas also helped to establish two Christian mental health initiatives: the Living Water Counselling Centre in Toronto and the East Mental Health Team with the Evangelical Medical Aid Society China. In his spare time he also obtained a Masters in Christian Studies from Dallas Theological Seminary. He serves actively as the chair of the Deacons Board of the Scarborough Chinese Baptist Church. Thomas is married to Jeanette and has two grown children and 6 grandchildren.