Hāshim
23 years, 285 days
https://en.m.wikipedia.org/wiki/Hussein,_Crown_Prince_of_Jordan
Abdullah II
Hereditary and elective (presumably Hussein, Crown Prince of Jordan)
Abdullah, a constitutional monarch, liberalized the economy when he assumed the throne, and his reforms led to an economic boom which continued until 2008. During the following years Jordan's economy experienced hardship as it dealt with the effects of the Great Recession and spillover from the Arab Spring, including a cut in its petroleum supply and the collapse of trade with neighboring countries. In 2011, large-scale protests demanding reform erupted in the Arab world. Many of the protests led to civil wars in other countries, but Abdullah responded quickly to domestic unrest by replacing the government and introducing reforms to the constitution and laws governing public freedoms and elections. Proportional representation was introduced to the Jordanian parliament in the 2016 general election, a move which he said would eventually lead to establishing parliamentary governments. The reforms took place amid unprecedented challenges stemming from regional instability, including an influx of 1.4 million Syrian refugees into the natural resources-lacking country and the emergence of the Islamic State of Iraq and the Levant (ISIL).
Rania Al-Yassin