Mr Battin is the fourth opposition leader to stump up to Victoria's Labor government after ousting Mr Pesutto in a party room meeting that heralded the return of expelled MP Moira Deeming.
Mr Pesutto opted not to run and Mr Battin was elected above Mornington MP Chris Crewther, while opposition financial spokeswoman Jess Wilson's tilt at the top job failed to pass the first round of voting.
Former tennis player Sam Groth was elected unopposed as deputy leader, while David Davis has been elevated to leader of the upper house, with Evan Mulholland retaining his deputy upper house leader role.
"I'm very thankful for the support I've got from my colleagues in the party room today to ensure that we could come out united," Mr Battin said after the vote on Friday.
Introducing himself as a former police officer and small business owner, the MP for Berwick said he was a political outsider who understood what Victorians were going through under Labor.
He nominated the cost of living, crime, budget repair and roads as issues he would focus on over the next 700 days until the state election in November 2026.
"Every time a small business is charged more tax, customers are charged more for the items they buy, increasing the pressures on cost of living in our state," he told reporters on Friday.
"It'll be our goal to have reduced taxes to release the pressure on businesses across the state."
Mr Battin pledged to crack down on out-of-control crime in the state, fix "crumbling" regional roads and run smaller governments.
John Pesutto chose not to contest the leadership, stepping aside from the role. (Joel Carrett/AAP PHOTOS)
But the new leader was forced to defend his democratically elected leadership group which does not feature women.
"We have got very strong performing women within the partyroom who will be on the frontbench moving forward," he said.
Mr Battin praised his predecessor as a "great man" and a "stalwart of the party", vowing to work with him in a united party.
Mr Pesutto congratulated the new leader, vowing to stay on in parliament.
"I wake up every day and I'm very honoured and privileged to serve the people of Hawthorn," the outgoing leader said.
Mr Groth appeared to spark the leadership spill earlier in December, when he resigned to the backbench after Mr Pesutto refused to step down as leader following a defamation loss.
A Federal Court judge found Mr Pesutto had defamed Mrs Deeming by implying she was associated with Nazis who gatecrashed a controversial Melbourne rally she attended and ordered he pay her $315,000 and costs.Â
Independent MP Moira Deeming has been welcomed back into the Victorian Liberal Party. (Joel Carrett/AAP PHOTOS)
It was the second time the party voted on whether to return Mrs Deeming, the first was rejected after Mr Pesutto cast the tie-breaking vote in an issue that split the party down the middle.
Mrs Deeming expressed her delight after the vote to allow her to return.
"The unjust allegations and expulsions have been overturned and I'm back in the Liberal parliamentary party room where I belong," she told reporters on Friday.
"I'm very grateful to everyone who lobbied to get this done, both inside and outside the Liberal Party."
Ms Wilson had announced her candidacy after a deal to become Mr Battin's deputy came off the table.
Labor minister Mary-Anne Thomas said the Liberals had been consumed by in-fighting while bushfires burned, labelling Mr Battin a "hard-right" politician who was disconnected to the concerns of Victorians.
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