There had been outcry when it was first revealed he was in the running, following years of controversial comments and behaviour.
Campaigners have labelled Mr Abbott a homophobe, a misogynist and more in the last few days.
Below, we collect a few of his most polarising moments.
‘Coal is good for humanity’
The world has heard much in recent years from another outspoken politician on the virtues of “beautiful, clean coal”, but Tony Abbott got there before Donald Trump.
In 2014, while prime minister, he attended the opening of multi-billion-dollar coal mine in Queensland and spoke out against criticism of coal.
“Energy is what sustains our prosperity, and coal is the world’s principal energy source and it will be for many decades to come.”
As a fossil fuel, coal contributes to global warming when burned for power and pollutes both the air and water.
‘Ditch the witch’
Not a comment by Mr Abbott, but a banner next to which he campaigned against Australia’s carbon tax in 2015.
He addressed opponents of the measure from a podium in front of Parliament House in Canberra, flanked by protesters holding signs describing then-PM Julia Gillard as a “witch” and a “b***h”, images show.
Mr Abbott later said he regretted that some people had gone “over the top” in their criticism of Ms Gillard.
This took some ironing out
Five years earlier, in 2010, it was also carbon offsetting that provided Mr Abbott a chance to offend.
Visiting a dry cleaner’s, he said that an emissions trading scheme championed by Malcolm Turnbull would damage small businesses through increased power costs.
But he also addressed Australian women directly on the matter, saying: ”What the housewives of Australia need to understand as they do the ironing is that if they get it done commercially it’s going to go up in price, and their own power bills, when they switch the iron on, are going to go up.”
He was forced to climb down sheepishly from his remark some time later, ironing his own shirt for the cameras.
‘Threatened’ by homosexuality
Again in 2010, Mr Abbott told a television interviewer he felt “probably feel a bit threatened ... as most people do” by the concept of homosexuality.
Provided a chance to clarify on a different programme, he admitted it had been a “spontaneous” answer.
He added: ”The truth is I try to take people as I find them. I’ve always tried to be that way and I hope as I get older I become better at it.”
However, reports said at the time, he did not explain exactly what he felt threatened by.
He also told the second interviewer that homosexuality “challenges, if you like, orthodox notions of the right order of things”.
Opposition to same-sex marriage
In 2017, as the fraught Australian debate on this subject raged, Mr Abbott derided the idea of extending marriage to gay couples as “political correctness”.
Mr Abbott is Catholic, and attended seminary in his younger years. In 2016 he spoke at an Assembly of Catholic Professionals luncheon and, addressing the topic of same-sex marriage, said: “Who would have thought even 10 years ago that which has been taken for granted for millennia would be so questioned?”
He also penned an op-ed for The Sydney Morning Herald, which was more nuanced than his “political correctness” jibe.
Mr Abbott was caught winking at an ABC radio host when he was told a caller he was about to be introduced to was a phone sex worker.
The woman informed the then-PM she had been forced to work on a phone sex hotline to make ends meet. Unfortunately for Mr Abbott, he appeared to have forgotten he was being filmed.
He later said: “I was looking at [the studio host], he was smiling at me and I winked back at him. I shouldn’t have done it.
“I should’ve been more focused on the caller and more focused on the interview.”
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