He learnt politics early. He stood by his grandfather, King Abdullah, in the al-Aqsa mosque in Jerusalem in 1951 as he was shot dead by a Palestinian. Two years later, after his father abdicated because of mental illness, he became King.
Educated at Harrow and Sandhurst, he made an early effort to show that he was not a pawn of colonialism by dismissing his British military adviser, Pasha Glubb. It was to be a recurring theme of his reign. He needed to keep in with the foreign powers but preserve his nationalist credentials.
The core of his regime was the bedouin army. King Abdullah had seized the West Bank in 1948 and paid for it with his life. The Palestinians resented Jordanian rule. In 1957 he just survived an attempt to topple him by nationalists by appealing to the military as the country tottered towards civil war. Beyond Jordan he looked to the US as his guarantee of survival.
The loss of the West Bank to Israel in the 1967 war again put his survival in doubt. In the aftermath, Jordan became the base for Palestinian guerrillas and the target of Israeli attack.
Supported by Israel and the US, the King moved against them during the so-called Black September, as the army fought the Palestinians in a savage civil war. Three years later he flew to Israel to warn its disbelieving prime minister that Egypt and Syria were about to attack.
He worked with the CIA and the US covertly and overtly, but this did not stop him opposing the US-led war against Iraq in 1990. At one moment he was allied to Syria, but allowed Jordan to be used as a base to overthrow its government in 1978.
He paid paid a heavy price for his stance in the Gulf war. He was ostracised by Saudi Arabia and Kuwait. Some 350,000 Palestinians expelled from the Gulf were forced to return home. The US was chary of its former ally.
Agreement between Israel and the Palestinians in Oslo in 1993 promised further isolation. The King reacted quickly. He signed a peace treaty with Israel in 1994. The next year he broke with Iraq, receiving Hussein Kamel, the defecting son-in-law of Saddam Hussein.
Married four times and the father of 11 children, there was always a potential problem over his succession. His brother, Crown Prince Hassan, was appointed in 1965, when the king was a target for assassination. But last month he appointed Abdullah, his oldest son, as his heir. Once again the future of Jordan is in the balance.