Chief Executive Leung Chun-ying has made a surprise announcement that he will not seek re-election due to family reasons.
"If I run my family will suffer intolerable stress due to my electioneering ... I must protect them," he told a press briefing.
He told reporters his decision was not due to the central government not endorsing him.
"[Beijing] has always supported me and said I have done a good job," Leung said.
Asked if the decision was because of his daughter Leung Chai-yan's condition, he said he did not want to delve too much into his personal life, but said: "As a husband and father I have a responsibility ... My daughter has only one father, and my wife has only one husband."
Chief Executive Leung Chun-ying meets the media on Friday. Photo: Felix Wong
On Thursday night, he was seen at Prince of Wales Hospital in Sha Tin, where Chai-yan was rumoured to be receiving treatment.
He added that his past political career had already impacted his family.
Leung had repeatedly told media "there was no message" yet when asked whether he would seek a second term in March.
During a trip to an Asia-Pacific Economic Cooperation meeting in Peru last month, Leung told the media that President Xi Jinping had approved of his work in office, but he later said people should not "over-interpret" the remarks as being any endorsement of further political ambitions.
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Leung assumed office as Hong Kong's fourth chief executive in 2012, succeeding Donald Tsang Yam-kuen. Leung was a member of the Executive Council from 1997 to 2011, prior to taking over the top spot.
If I run my family will suffer intolerable stress due to my electioneering ... I must protect them.