Scott Morrison has been sworn in as Australia's next Prime Minister.
Mr Morrison won a leadership contest against Peter Dutton 45-40 on Friday.
The leadership ballot was called after former prime minister Malcolm Turnbull agreed to the second leadership spill this week.
Governor-General Peter Cosgrove conducted the ceremony at Government House to officially make Mr Morrison the nation's 30th Prime Minister.
Mr Morrison has described himself as the new generation of Liberal leadership who is "on your side".
He thanked Mr Turnbull as a great Australian who has contributed a great deal to the country.
The Liberal Party decision ends Malcolm Turnbull's three years as PM.
Earlier, Mr Turnbull thanked the Australian people and listed achievements including tax cuts, same-sex marriage and jobs growth.
He said his successor had been a very loyal and effective treasurer.
The outgoing PM lashed out at the wreckers he said had created chaos.
He said there had been a determined insurgency trying to, "if not bring down the Government, then bring down my prime ministership".
"I was impressed by how many of my colleagues spoke or voted for loyalty above disloyalty, how the insurgents were not rewarded," he said.
"The people who chose — Peter Dutton and Tony Abbott and others — who chose to deliberately attack the Government from within, they did so because they wanted to bring the Government down."
Mr Turnbull said he would be leaving Parliament very soon, which means there will be a by-election for his Sydney seat of Wentworth.
In a pointed sign, Mr Turnbull did not call on any News Corp journalists to ask questions at his final media conference.
The spill has exposed the level of bitterness inside the party. Moderate Trent Zimmerman said it had been a "horrific week".
After being defeated, Mr Dutton said he would provide "absolute loyalty" to Mr Morrison.
"To make sure we win the election, that we defeat Bill Shorten to make sure that he's never Prime Minister," Mr Dutton said.
His supporters had been pushing for the leadership change including circulating the petition to force a meeting.
But the move backfired with Mr Morrison winning the ballot.
Former PM Tony Abbott left the meeting saying "we've lost the Prime Minister but there is still a government to save".
"That is what all of us will do our best to do now," Mr Abbott said.
Long-serving deputy leader Julie Bishop has also lost her position to Victorian Josh Frydenberg who defeated Greg Hunt and Steve Ciobo.
Mr Morrison will emerge from a chaotic and crisis-filled week in Federal Parliament as the nation's 30th PM.
The 50 year old has served as Mr Turnbull's Treasurer since the last leadership change in September 2015.
He cited drought policy as one of his first priorities as well as electricity prices and health policy.
He announced Mr Frydenberg would replace him as treasurer.
"I wish him well with that task, it's a tough one mate, I can assure you, I know you will do a great job with it," Mr Morrison said to his new deputy.
He said Mr Dutton would be welcome to play a role in the Government, "if he so chooses".
Mr Morrison praised outgoing deputy Liberal leader Julie Bishop.
"She has been a rock star for the Liberal party as a foreign minister, and for Twitter and Facebook," he said noting her expansive social media presence.
"She has been an amazing contributor and driver of foreign policy and an advocate for Liberal values from one end of this country to another and one end of this world to the other," he said.
Mr Morrison said he would talk to Ms Bishop about what role she wanted to play in the Government.
Ms Bishop has so far not commented on her intentions.
Mr Morrison said he looked forward to his first electoral test but suggested the federal election would be next year.
The closeness of the vote reflects the deep divisions in the Liberal Party.
Frontbencher Melissa Price supported Mr Turnbull and described it as an emotional meeting.
She said Mr Morrison gave a powerful speech after his victory.
Ms Price said the new leader described 10 years of "sniping, negativity and instability" and he said "the time is for us to put that all behind".
She told the ABC Mr Turnbull appeared shocked by the closeness of the result.
"I think he could not believe how close it was that we had gone through all of this during the week and we really hadn't progressed that much," she said.
Shorten wishes Turnbull well
Labor leader Bill Shorten said Australian politics needs people like Malcolm Turnbull.
"For all our verbal conflict, for all the fierce words we've exchanged, I hope Malcolm knows that I have always respected him as a formidable opponent," Mr Shorten said.
He described Mr Turnbull as an advocate of great intellect and eloquence and as someone who came to parliament relatively late in life, because he was driven by the desire to serve.
He commented on how frequently his outgoing opponent used the word 'love'.
"Anyone who listened to him speak could always hear his deep and profound love for his wife Lucy, for their children and their grandchildren," Mr Shorten said in a statement.
"But also his abiding love for our country.
"I hope the future brings Malcolm plenty of relaxing paddles in the kayak, plenty of stories to read and re-read to the grandchildren and many long and happy days with his loved ones."
