Sydney, Australia: Malcolm Turnbull, who will become Australia's next prime minister after winning a leadership challenge Monday, is a millionaire former banker whose socially liberal views including support for gay marriage are at odds with some of his fellow conservatives.

The 60-year-old Sydneysider, said to be worth upwards of Aus$100 million (US$71 million), has led the right-wing Liberal Party before -- serving as opposition leader for just over a year from September 2008. 

But he was dumped when he refused to abandon a carbon emissions trading scheme designed to combat climate change, a policy many in his party rejected. 

His moderate views on social issues have also caused waves, including his backing of gay marriage which is not legal in Australia. But he remains popular with business leaders because of his background in law, banking and communications.

The silver-haired Turnbull, after defeating incumbent Prime Minister Tony Abbott 54-44 in a party room ballot, stressed he would lead a government that was consultative and collaborative and which would also showcase a smarter style of leadership in a complex world.

‘My firm belief is that to be a successful leader in 2015, perhaps at any time, you have to be able to bring people with you by respecting their intelligence in the manner you explain things,’ he said.

In some quarters Turnbull has a reputation for being arrogant, and his staggering wealth means he risks being seen as out-of-touch with ordinary Australians.

But the witty and eloquent Turnbull is an adept user of social media, and he may also be seen as the best hope of winning over swing voters who would otherwise side with the opposition Labor party.

In a revealing interview in 2012 Turnbull admitted to the Sydney Morning Herald that he was ambitious but said: ‘I would not want to be prime minister of Australia at any price.’

Earlier Monday, he said that electoral defeat was staring Abbott in the face and change was needed ‘for our country's sake, for the government's sake, for the party's sake’. 

- Humble beginnings - 

Malcolm Bligh Turnbull was raised by his single parent father, after his mother left the family when he was still in primary school, and he was educated at Sydney Grammar with the help of a scholarship.

A Rhodes scholar at Oxford, Turnbull worked as a journalist before turning to the law.

He gained prominence in the 1980s for successfully defending former MI5 agent Peter Wright against the British government in the ‘Spycatcher’ trial.

From law he entered the corporate world, becoming a merchant banker and investing in technology start-ups, before entering public life by spearheading the push for Australia to break ties with British royalty and become a republic.

The campaign was unsuccessful, but by October 2004 he had entered parliament and under Liberal prime minister John Howard rose to be environment minister.

When Howard was swept from power in 2007, Turnbull was not the first choice to lead the party. But, ever a contender, he was opposition leader within a year. 

His subsequent loss of the Liberal leadership, which went to Abbott by just one vote, was a crushing defeat for Turnbull who at first contemplated resignation from politics.

He was persuaded to stay on, however, and as Abbott's communications minister has worked hard to sell government policies.

But with the government's opinion polling in the doldrums, some had seen Turnbull as the moderate who could deliver the conservatives the next election, due by January 2017.

The Labor Party had previously planned to paint him as ‘Tony Abbott in an expensive suit’ -- a millionaire with a mansion on Sydney harbour and a big ego who is out of step with his own colleagues.