At a media briefing on Friday, Cheung didn’t reveal whether it was his idea to stand down.
He said he was grateful for the trust and support that he had been given by the central government, and the chief executives he worked for.
“It has been my true honour and privilege and given me much satisfaction to have served the Hong Kong community for nearly 50 years in various positions,” he said.
“Especially, in my service for the country and the Hong Kong Special Administrative Region, as well as of course, participation in the implementation of the very important one country, two systems arrangement since Hong Kong’s return to the motherland.”
Chief Executive Carrie Lam thanked Cheung for his service, saying he had made great contributions to Hong Kong.
Lam said she wished him good health and a happy life.
Cheung is being replaced by Security Secretary John Lee, who is in turn being replaced by Police Commissioner Chris Tang. One of Tang’s deputies, Raymond Siu, is becoming the SAR’s new police chief.