Kogarah MP Chris Minns was elected unanimously as NSW Labor leader on Friday after Michael Daley withdrew his candidacy for the leadership.
Mr Minns has long held leadership ambitions and has twice failed to secure the leadership, losing to Mr Daley in 2018 and Jodi McKay in 2019.
Mr Minns claimed he was "humbled" to have been elected leader and said the "hard work" was just beginning.
"Now the hard work begins for the Labor party to get up off the mat and take the fight to the Berejiklian government and have some positive plans for the future of NSW," Mr Minns said.
"I know that task will be difficult. I believe I am up to it."
Mr Minns will select his opposition frontbench before Parliament resumes on Tuesday.
He said he would like former leader Jodi McKay to take a shadow ministry if she wants one.
"I'd love to have her in a senior role, but I have to have discussions with her to work out where that will be," he said.
Mr Minns sought to clarify his previous statements regarding taking a more positive approach to the Opposition Leader role and not criticising everything the government does.
He said that did not mean the opposition under his leadership would not hold Gladys Berejiklian and the government to account.
"I do want to be positive, we should be positive if we believe they've done a good job, but where we believe they have fallen short and cost the taxpayer money, or outright done the wrong thing, then we will be on the side of the taxpayer," he said.
"We will give credit where it is due and hold them to account if they need to do better."
The new Opposition Leader said he would tackle his role as the Member for Kogarah with equal vigour as his new role.
"I am committed to being the Member for Kogarah. It is the thing professionally that I am most proud of," he said.
"The things that people in the Kogarah electorate care about the wider community care about. Tolls, cost of living, transport, schools and health among them.
"As the leader of the Party, I feel I could do good things for the Kogarah electorate whether that is in opposition or government as I will have a bigger pulpit and a bigger voice."