On 18 December 2012, Zhang started serving as director of the Liaison Office of the Central People's Government in the Hong Kong Special Administrative Region and spearheaded the CCP's efforts against the democratic movement in the former British colony.

In a widely reported incident he stated to pro-democratic legislative council member Leung Yiu-chung that "the fact that you are allowed to stay alive already shows the country's inclusiveness".

He was demoted, in February 2020, during the widespread anti-government protests and the COVID-19 pandemic affecting Hong Kong, to a deputy directorship of that office.

[7] In January 2021, Chief Justice Geoffrey Ma responded and said that the judiciary should not be reformed simply due to the pro-Beijing party being unhappy with the court's rulings.

[7] In March 2021, while on a trip to Hong Kong to survey opinions about planned changes to the electoral system to implement "patriots" ruling the government, Zhang claimed that he met with pan-democrats, without specifically naming any.