1. King Bhumibol Adulyadej (Thailand): 63 years
Born: 5 December, 1927
King Bhumibol, who was in fact born in Massachusetts, USA, tops the list as the world’s longest serving current leader and will go down as the longest serving Thai monarch in history. Despite being a constitutional monarch, King Bhumibol, whose regnal name is Rama IX, is a popular and revered figurehead who still has an important role in settling many national political issues.
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