Dominic Perrottet has built a name for himself as a conservative poster-boy and economic reformer but will now be written into the history books as the 46th person to become NSW premier – and the youngest in its history.

Perrottet – from the party’s right faction – defeated moderate Rob Stokes in an overwhelming party room victory, garnering 39 votes to five on Tuesday to replace Gladys Berejiklian as the state’s Liberal Party leader and premier.

In a deal struck after days of behind-the-scenes factional wrangling, Penrith MP Stuart Ayres was appointed deputy leader and moderate faction powerbroker Matt Kean is expected to be promoted to treasurer.

Berejiklian quit on Friday after the state’s corruption watchdog disclosed she was under investigation for potential breaches of public trust given her secret five-year relationship with former MP Daryl Maguire.

Turning 39 only a fortnight ago, Perrottet is the youngest person to become NSW premier. Kristina Keneally, Nathan Rees and Nick Greiner were all 40 when they assumed the state’s top office.

Long touted as the ‘heir apparent’ to Berejiklian, the vote completes the devout Catholic’s meteoric rise to the top – completed only a decade after he became an MP.

Perrottet immediately pledged to be premier for families and to stay the course on the state’s COVID-19 plan to get out of lockdown and live with the virus.

“Up until now, all of our Liberal premiers have been infrastructure premiers – building roads, rail, schools and hospitals for communities right across our state,” he told reporters.

“That will not change with me, but I will also be a family premier, focusing on how we can make life better for working families.”

One of 13 children – one of whom died at birth – born to a World Bank economist, Perrottet grew up in West Pennant Hills and attended the Catholic school Redfield College in Dural.

He went on to study commerce and law at the University of Sydney, where he began to make a name for himself in student politics.

In 2005, at the age of 22, he was appointed president of the NSW Young Liberals, following in the footsteps of an eminent class of politicians that includes Berejiklian, former prime minister John Howard and state party president Philip Ruddock.

Then came a stint on the NSW Liberal Party executive between 2008 and 2011, when a by-then 28-year-old Perrottet first set foot in the Legislative Assembly as the member for Castle Hill.

Since then Perrottet has bounced around three electorates in as many terms – Castle Hill, Hawkesbury and Epping – and served as minister for finance and industrial relations before becoming treasurer and deputy party leader in 2017.

In that time the father of six has managed to keep his nose mostly clean.

As treasurer, he has argued for national GST reform and has pushed to phase out stamp duty – which netted the government $9.3 billion in the last financial year – in favour of an annual property tax.

But he clashed with Prime Minister Scott Morrison over federal financial support for shut down businesses during the current COVID-19 lockdown.

And as the minister responsible for the state’s scandal-ridden worker’s compensation insurer icare, Perrottet came under fire after the agency underpaid thousands of injured workers by up to $80 million.

A member of the NSW government’s COVID-19 crisis cabinet, he was back in the headlines in July after reports emerged that he opposed the extension of the lockdown of Greater Sydney, arguing the dire economic impacts meant it was time to learn to live with the virus.

The outbreak has since killed more than 350 people.

His personal views on social issues have also drawn ire from some quarters.

Both he and rival Rob Stokes voted against the decriminalisation of abortion, which has ramifications for voluntary assisted dying legislation, due before the parliament this year.

He opposed the legalisation of same-sex marriage, has previously warned “throwing money” at welfare was contributing to rising divorce rates, has described some climate change policies as a “gratuitous waste” and in 2016 called Donald Trump’s election as US President “a victory for people who have been taken for granted by the elites”.

– AAP