Blinken, who will head later Thursday to Turkey, has called for an "inclusive" process to form Syria's next government that includes protections for minorities after Islamist-led rebels ended the repressive rule of Assad, a member of the Alawite community.
Meeting King Abdullah in the Red Sea resort of Aqaba, Blinken, who leaves office in little more than a month, promised US support for "the stability of Syria's neighbours, including Jordan, during this period of transition", State Department spokesman Matthew Miller said.
Blinken called for "an inclusive transition that can lead to an accountable and representative Syrian government chosen by the Syrian people", Miller said.
He also said the United States hoped to ensure that Syria is not "used as a base for terrorism" and does not pose "a threat to its neighbours" -- a key concern both for Turkey, which resents the US military alliance with Syrian Kurds, and Israel, which has been pounding sites across its historic adversary since Assad fell.
King Abdullah in his meeting with Blinken "reaffirmed Jordan's respect" for "the Syrian people's choices, stressing the need to safeguard Syria's security and the safety of its citizens", a palace statement said.
It is Blinken's 12th visit to the Middle East since the October 7, 2023 attack by Hamas Palestinian militants on Israel, which has responded with a relentless military campaign in Gaza.
His previous trips have ended in disappointment as he sought a ceasefire between US ally Israel and Hamas.
King Abdullah, while discussing Syria, told Blinken that "the first step to reach comprehensive regional calm is to end the Israeli war on Gaza", the palace statement said.
Blinken in his meeting agreed there was an "urgent need" to reach a Gaza ceasefire that includes the release of hostages held by militants, Miller said.
President Joe Biden's administration leaves office on January 20.
President-elect Donald Trump has described Syria as "a mess" and said that the United States should not get involved, although he has not elaborated on US policy since Assad's ouster.
