It's virtually impossible to have a conversation about Mr Turnbull without the phrases 'doesn't suffer fools gladly' or 'a force of nature' popping up.

But is he brilliant and charismatic or arrogant and power hungry? That depends on who you ask.

Born in October 1954, Mr Turnbull, 53, is ambitious, intelligent, and relishes a good challenge. He is also attractive and quirky: his website features a dog blog, which includes an obituary to his pet Rusty.

But even some in his own party argue he is a lone wolf who finds it difficult to consult and can be a ruthless one-man band.

There's no question Mr Turnbull has an impressive CV.

He graduated from Sydney University with an arts/law degree and studied for a second law degree from Oxford as a Rhodes Scholar.

While at Oxford he met Lucy Hughes, daughter of Tom Hughes, Australian attorney general from 1969 to 1971. They married in England in 1980 and have two children, Alexander and Daisy. Lucy, also a lawyer, was the first female lord mayor of Sydney in 2003.

Mr Turnbull has already had more than his 15 minutes in the sun in high-profile legal cases, such as when he defended the right of MI5 agent Peter Wright to publish his memoir, Spycatcher, in 1986.

He also enjoyed stellar success as a journalist and merchant banker before entering politics.

In 1987, he set up an investment banking firm in partnership with former New South Wales Labor premier Neville Wran and Nick Whitlam, son of former Labor prime minister Gough Whitlam. He was chairman and managing director of Goldman Sachs Australia, and he made millions as co-founder of internet provider OzEmail.

Most famously, he was chair of the Australian Republican Movement from 1993 to 2000, and was the driving force behind the 1999 referendum. Mr Turnbull was attacked mercilessly in the media as arrogant and elitist, and the republican model he backed for Australia - electing the president by a two-thirds majority of Parliament - was blamed for the resulting 'no' vote. But Wentworth, the electorate he has represented since 2004, registered the highest 'yes' vote in the country. After that loss, he said the republican question was unlikely to re-emerge until after the death of Queen Elizabeth, a view he repeated days ago in response to Prime Minister Kevin Rudd's invitation to collaborate on the issue.

Mr Turnbull again came to prominence in 2003 during a bitter preselection battle for Wentworth, ousting the Liberal sitting member Peter King amid claims of rampant 'branch stacking', when people are given inducements to join the party.

Said to be worth more than A$120 million (HK$756 million), Mr Turnbull used his first press conference as leader to tackle the perception he was born to wealth, speaking of how he was raised by his father in a small rented flat. His mother, Coral Lansbury, a literature academic, and his father Bruce, a broker, separated when he was nine years old, and his father struggled to send him to costly Sydney Grammar School as a boarder.

'I do not come to the position of leader of the Liberal Party from a lifetime of privilege. I know what it's like to be very short of money,' he said.

He has brought a new optimism to conservatives in Australia. Former New South Wales Liberal opposition leader Peter Debnam said Mr Turnbull would have a very quick impact. 'He's very determined and energetic,' he said.

And Liberal City of Sydney councillor Shayne Mallard, who campaigned with him extensively during the last federal election, described him as an ambitious man who was fiercely loyal to his family and proud of his humble beginnings and of his success.

'And so he should be. He is proactive, engaging and very effective. I sent him a note saying that if he energises Australia the way he has energised Wentworth, he'll be a great leader and prime minister.'

Mr Mallard said the usual criticisms levelled at Mr Turnbull were characteristic of his early business career, but that he had adjusted to the different culture of being a politician.

'That's part of his success. He's able to learn quickly. And Lucy is a tremendous asset to him in helping him understand political subtleties. He's quickly adapted to public life and it fits him comfortably.'

Not everyone is singing the same tune. A senior Liberal who asked not to be named described Mr Turnbull as a bully. 'He has a very good working knowledge of dirty tricks, both corporate and political,' he said. 'It would be a bad day for Australia if he came anywhere near the Lodge [prime ministership] because he would put his own interests first. Turnbull has been falling all over himself to get to power. There's a significant faction in the [Liberal] party who don't think he's made of the right stuff and that he will turn on anyone when it suits him.'

Mr Turnbull is the first republican and only the second Catholic to lead the federal Liberal Party.

As the environment minister to former prime minister John Howard, he was visibly uncomfortable with Mr Howard's hard line on climate change; he was in favour of an apology to indigenous Australians for historic grievances, and supports gay rights but not gay marriage.

Not much is known of his foreign policy leanings, especially regarding China, but he is known to be an Iraqi war sceptic and backs a two-state solution for Israel and the Palestinian Territories.