The father of six had long been touted as a potential future premier of the state, rising quickly through the ranks to become a key figure of the NSW Liberal Party.
“I’m very passionate about freedom,” Mr Perrottet said on Monday ahead of the leadership vote.
“Freedom is the overarching value that I hold and that is that people of different religions, cultural backgrounds have a great place in our society.”
Prior to his ascension to the top job, Mr Perrottet had become the state's treasurer and deputy leader of the party in 2017, after first entering state politics in 2011.
He has spoken about how his religious beliefs have had a fundamental influence on his work in politics, including framing his views on issues such as abortion.
Past statements from Mr Perrottet to gain renewed attention since announcing his tilt at the leadership include a social media post praising Donald Trump’s election as US president in 2016.
He has also previously warned Australia should stop “throwing money” at welfare because it is contributing to rising divorce rates and described the approach of some to climate change as a “gratuitous waste”.
Time for a 'conservative spring'
In 2016, Mr Perrottet declared it was time for a "conservative spring" following the election of former US President Donald Trump.
In a post on his official Facebook account, Mr Perrottet described the election win as "a victory for people who have been taken for granted by the elites".
“If you stand for free speech, you are not a bigot," part of the post reads.
"If you question man-made climate change, you are not a sceptic. If you support stronger borders, you are not a racist.
"If you want a plebiscite on same-sex marriage, you are not a homophobe.
"If you love your country, you are not an extremist.
"These are mainstream values that people should be free to articulate without fear of ridicule or persecution by the left."
Climate change devotion a 'gratuitous waste'
A year earlier, Mr Perrottet had also described the “almost religious devotion of the political left to climate change” as an example of “gratuitous waste” when addressing a conservative think tank.
He later stated that he believes in the “science of climate change” but defended his comments saying they reflected criticism of the approach of some to addressing the problem.
Other comments that attracted attention include previously pointing out a connection between Australia’s welfare system for rising divorce rates and declining fertility.
In a speech to the Centre for Independent Studies (CIS), Mr Perrottet quoted the US politician Daniel Moynihan’s view that “marriage was penalised and single parenthood subsidised” by the welfare system.
"Some have argued that social security replaces the role of children in old age by socialising the traditional duties of the family," he said.
“As one commentator has asked, why have children at all when the state will take care of you in your old age?”
'Faith is important to me'
A devout Catholic, Mr Perrottet voted against decriminalising abortion in 2019 - warning supporters of the legislation they were on the “wrong side of history".
At the time, he said he couldn’t support laws that stopped “the beating heart of an unborn child”.
“Faith is important to me and my view in the Liberal party when it comes to those types of issues - we always have a conscience vote,” said Mr Perrottet, addressing the matter on Monday when questioned by reporters.
“People shouldn’t be ruled out of public life because they have a Christian faith.”
In 2015, he also spoke in defence of the Catholic Church publicly distributing a booklet in their school system outlining their views same-sex marriage.
"Our right to free speech comes with the responsibility to not incite violence or hatred," he said.
"Arguing your view on the definition of marriage clearly passes this test."
Mr Perrottet has also opposed laws to force priests to disclose child abuse arguing “the confessional seal is sacrosanct for every priest in every penitent no matter what sins are confessed”.
He has foreshadowed that he would push for a conscience vote on the consideration of assisted dying laws in NSW.
Previous political challenges
More recently, Mr Perrottet faced criticism last year for his handling of the $38 billion state-run insurance scheme icare.
The scheme is supposed to look after millions of workers when they get sick or injured on the job but has faced scrutiny for leading to underpayments through mismanagement.
“When you make mistakes in public life you put your hand up and say I made a mistake,” Mr Perrottet said on Monday, in relation to the scheme.
“I still believe despite the challenges - that scheme is better than where it was when I took over.”
He also gained media attention for opposing an extension to NSW's lockdown in July, arguing it was time to change the thinking on COVID-19 and to learn to live with infections.
The NSW treasurer also entered into a dispute with the federal government over the need for more economic support - calling on them to reinstate JobKeeper as the Delta outbreak took hold.
Following this, he became one of the architects of a financial rescue package to provide support to those who had lost hours of work during the pandemic.
What his leadership will look like?
Mr Perrottet first entered politics after winning the safe Liberal seat of Castle Hill, before changing seats to Hawkesbury in 2015 and later the northwest Sydney seat of Epping, ahead of the 2019 election.
In his inaugural speech, he declared he would lead based on the ideals of sacrifice, generosity, freedom and opportunity.
"I believe in freedom, because it is only by exercising freedom that individuals can develop the habits of generosity, hard work, fairness and concern for others," he said.
"I believe that these habits have made our country great and are ultimately the foundation for the pursuit of the good life. You cannot do good without striving to be good."
He succeeds former premier Gladys Berejikilian who last Friday announced her resignation amid an investigation by the state's anti-corruption watchdog.
Mr Perrottet has argued his leadership will help ensure stability as the state prepares to reopen to fully vaccinated people on 11 October after more than 100 days of COVID-19 lockdown.
He is expected to continue to lead with a focus on the economy and economic reform as the state's premier.
“We all want to get the kids back in the classroom, we all want businesses to be open, we all want people back in work,” Mr Perrottet said.