Tsang joined the Immigration Department as an Assistant Immigration Officer in 1987. In 1991, he was promoted to Immigration Officer and Senior Immigration Officer in 2000. He was a Chief Immigration Officer in 2004, to Assistant Principal Immigration Officer in 2007 and to Principal Immigration Officer in 2009. He had become the Assistant Secretary fot Security from 2003-2006. In 2012, he became Assistant Director of Immigration in 2012 and Deputy Director of Immigration in 2014. In April 2016, he was appointed Director of Immigration.
| Director of Immigration
|Order of precedence|
Director of Immigration
| Hong Kong order of precedence
Director of Audit
Commissioner of Customs and Excise