Prince Abdullah bin Hussein, eldest son of King Hussein, was swept from his military barracks and plunged into affairs of state last month when his ailing father named him as heir.
Until then the 37-year-old prince, commander of Jordan's Special Forces in an army which forms the bedrock of support for the ruling Hashemite dynasty, had rarely been considered a leading contender for the throne.
Barely had King Hussein returned to the US for further treatment than the US Secretary of State, Ms Madeleine Albright, arrived in Amman to express support for the soldier prince.
Princes from royal families of Gulf Arab states and the son of Libyan leader, Col Muammar Gadafy, also came to Amman to voice their backing.
Prince Abdullah was born in Amman on January 30th, 1962, the son of King Hussein by his second wife, the English-born Toni Gardiner, known as Princess Mona.
He was sent to school in England, aged four, but completed his high school education in the US. He later took one-year courses in international affairs at Oxford University and Georgetown University in Washington.
In 1980 he joined the British Military Academy at Sandhurst and served in the British army in West Germany and Britain. He served in Jordan's 41st and 90th armoured brigades, the air force's Helicopter Anti-tank Wing and the Second Guards Brigade.
In 1993 he was appointed deputy commander of the Special Forces, assuming command one year later. He married Princess Rania in June 1993.
They have a son, Prince Hussein, and a daughter, Princess Iman.