By Chris Hogg
BBC News, Tokyo
Shinzo Abe is a political "blue blood". He comes from a dynasty that has already produced prime ministers - his grandfather and great uncle.
Shinzo Abe has emerged as a popular figure
His father was a foreign minister who missed out on the top job only after developing pancreatic cancer. So for some traditionalists it is only right and proper he should take his turn to "inherit" the premiership.
And yet by the usual Japanese standards he is quite young for a prime minister, at 52.
He has not got a huge amount of experience in the great offices of state. His previous role, Chief Cabinet Secretary, was his first cabinet job.
"He's relatively new to politics," says Professor Koichi Nakano, a political analyst from Sophia University in Tokyo.
"He's never held a portfolio that requires him to look into the details of social security, or diplomacy - a ministerial portfolio of any substance at all."
But he is popular. Before September's leadership vote, more than half the electorate said they supported him.
As Chief Cabinet Secretary - in effect the government's chief spokesman - he was highly visible, holding daily press conferences.
His tough stance on North Korea after the communist state's ballistic missile tests earlier this year swung many of the public behind him.
And it appeared he was groomed for the job by outgoing Prime Minister Junichiro Koizumi, and others within the Liberal Democratic Party (LDP). Before the vote Mr Koizumi gave him his explicit backing.
The LDP has governed Japan almost without interruption since 1955.
It is broadly conservative but contains different factions that compete for power.
The influence of the factions declined somewhat under Mr Koizumi but they are still important and they could prove a headache for the new man at the head of the party.
"Mr Abe's biggest challenge will be the formation of a new cabinet," argues Professor Masatoshi Honda from the National Graduate Institute for Policy Studies.
"If he doesn't get it right, and balance the demands of the competing factions, it could be difficult to preserve harmony within his team. In a way he will have to prioritise consensus-making rather than show strong leadership."
But others believe that Mr Koizumi's efforts to change the way politics is conducted will help Mr Abe.
"In the traditional LDP sense he does not have much power, since he is not the leader of a faction and he hasn't had a long career in which he could have accumulated favours from other MPs," says Tsuneo Watanabe, a fellow at the Mitsui Global Strategic Studies Institute in Tokyo.
"But in the new 'Koizumi' sense he does, because he's a popular figure who appeals to the voters. He could attract many people to vote for the LDP, which is probably the real reason why he was the preferred choice of so many party members."
So what will his priorities be?
Before the election Japan's leader-in-waiting gave few details of his preferred approach to economic policy.
We heard more about his desire "to create a new diplomacy under which Japan at times takes leadership and asserts opinions to set the world's rules".
Mr Koizumi has backed Shinzo Abe as his replacement
Some read this to mean Mr Abe's Japan will be a lot more assertive than it has been in the past, a change that could worry the country's Asian neighbours.
He also said he wants to rewrite the country's constitution which was drawn up by the Americans when they occupied Japan after World War Two.
And he is advocating a revision of Japan's Basic Law of Education from 1947, that would require schools to teach pupils how to love their country.
Such measures of course endear him to the more conservative elements in the LDP electorate.
But Dr Martin Schulz, Senior Economist at the Fujitsu Research Institute in Tokyo, warns that the new prime minister will run into difficulties, if he neglects economic reforms.
"The new prime minister will still have work to do to repair the country's public finances," he says.
"He needs to achieve major steps in pensions and public health reform. These will be very difficult to pull off, and will need swift and decisive action once he's confirmed in office."
Others though believe one of Mr Abe's first priorities will be to try to repair Japan's poor relations with its neighbours.
"Immediately after he takes office he will make a trip to Beijing for a summit with President Hu Jintao," is the bold prediction of Takao Toshikawa, chief correspondent of The Oriental Economist and a veteran analyst of LDP affairs.
"The biggest stick the opposition parties have to beat the LDP with is its weakness on Asian foreign policy. If he manages to secure a summit, that criticism will no longer be valid."
If he does do that, Mr Abe - Japan's 57th prime minister - will be following the lead given by his maternal grandfather Nobusuke Kishi, who was the country's 37th PM.
He visited several South East Asian countries shortly after taking office in 1957.
Mr Toshikawa believes Mr Abe has inherited his grandfather's "political DNA".
And those that try to paint him as a right-winger or a hawk are missing the point.
"He's a pragmatist, a realist" he says. "But expect some surprises."