By Agence France-Presse
Former home affairs minister Peter Dutton, an ex-police officer and right-winger, was the driving force behind the move to oust Turnbull after a Liberal Party backlash against his more moderate policies.
But after a torrid week of political manoeuvring in Canberra it was Morrison, a Turnbull ally who served as treasurer, who won a party vote 45-40.
Morrison -- an evangelical Christian known as "ScoMo" -- replaced a man who became the latest in a long line of leaders knifed in the back by ambitious colleagues.
The fresh outbreak of political instability was met with renewed disgust towards the political class -- already among the least trusted people in the country despite an unprecedented era of prosperity
Morrison admitted the extraordinary scenes in the nation's capital had taken a heavy toll on parliament and the Liberal Party.
"Our job... is to ensure that we not only bring our party back together, which has been bruised and battered this week, but that will ensure we bring the Parliament back together, that we can continue to work to ensure that our country stays close together."
He said his top priority was to help farmers in New South Wales struggling through one of the worst droughts in half a century.
"This is our most urgent and pressing need right now," Morrison said.
Dutton, who Turnbull accused of bullying and intimidation in the move to knife him, pledged to provide "absolute loyalty" to Morrison.
Turnbull, who pledged to quit parliament after his near three-year reign came to an end, survived one attempt to oust him on Tuesday, but ministers then began defecting, throwing the government into crisis.
His departure from politics will spark a by-election for his Sydney seat, threatening the government's wafer-thin one-seat parliamentary majority.
He used his final press conference to lash out at the "wreckers" in his party.
"There was a determined insurgency from a number of people both in the party room and backed by voices, powerful voices, in the media," he told reporters, in reference to media mogul Rupert Murdoch's conservative News Corporation.
"It was described as madness by many, and... in so far as there has been chaos this week, it has been created by the wreckers."
- Thwarted ambitions -
Dutton, who favours slashing migrant numbers and even pulling Australia out of the Paris climate agreement, was the sole candidate to be prime minister until Thursday when Morrison entered the fray to try to halt his power grab.
Former prime minister Tony Abbott, an arch conservative widely seen as the instigator of the move to get rid of Turnbull, said it was now important to "save the government" with national elections due by the middle of next year.
Morrison, a former immigration minister, who took credit for "stop the boats" -- a harsh policy to halt asylum-seekers from entering Australia -- is further to the right than Turnbull but not as hardline as some in the party.
Politics expert Rob Manwaring of Flinders University said Morrison was likely to continue Turnbull's economic agenda, of which he was one of the main architects as treasurer.
But he could shift the government's environment policy to the right as a consistent voter against the introduction of a carbon price.
"In one sense I think there would be continuity (in the economic portfolio), in another sense, (he'll be) trying to downgrade or shift any radical action on climate policy," he told AFP.
The unrest is the latest chapter in a turbulent decade for Australian politics, which has frequently descended into squabbling that has alienated voters.
No leader has managed to serve out a full term since former Prime Minister John Howard lost the 2007 election, in a remarkable revolving door at Canberra's parliament house.
One minister was so disillusioned with the push to oust Turnbull that he took to Twitter to apologise to the Australian people.
"Australia. We owe you an apology. I'm sorry. You deserve better than many of the things our Federal Parliament has served up to you for the past 10 years," wrote Nationals MP Darren Chester, whose party is in coalition with the Liberals.