[1] In April 2020, State Council of the People's Republic of China appointed Tsang Secretary for Constitutional and Mainland Affairs,[2] replacing Patrick Nip, days after the department had failed to reflect Beijing's controversially changed position on the status of the Liaison Office under Hong Kong's Basic Law.

[5] In August 2020, Tsang and ten other officials were sanctioned by the United States Department of the Treasury under Executive Order 13936 by President Trump for undermining Hong Kong's autonomy.

[9] In September 2020, when pro-democracy organizers planned to hold primaries for the 2020 Legislative Council, Tsang said that candidates could be in breach of the National Security Law.

[11] In January 2021, Tsang commented on forcing district councillors to take an oath to pledge loyalty to the government, and said that under the National Security Law, this would be required.

[12][13] After the arrest of 53 pro-democracy figures in January 2021, Tsang said that they had to pay the price for "crossing the red line" by organizing primaries for the Legislative Council.

"[17] In addition, on the potential changes to the electoral system from Beijing, Tsang said that "When the central government reaches a concrete decision, we will fully cooperate.

[25] In July 2022, when asked about changes that would only allow "patriots" to run for office, Tsang claimed that "In fact, democracy has taken a quantum leap forward since the return to the motherland in 1997.

[28] In May 2023, after District Councils had a reduction in democratically elected seats, Tsang defended the new changes and said "Therefore, any talk about elements of democracy, or talk about linking District Councils to the Special Administration Region's democratic progression, are complete misinterpretations of the original intention of the Basic Law, muddling up different concepts..."[29] Tsang said that "anti-China" forces used "loopholes" to "swindle" votes during the 2019 district council elections, where pro-democracy figures won the majority of seats; a change from the previous position, as Chief Executive Carrie Lam said at the time that the government respected the results.