Brian Gallant, 29, a lawyer from Moncton, became the third candidate to officially declare his candidacy for the party's leadership, which will be determined at a convention in October.
"There's no doubt that in the last year-and-a-half or so we've gone through some tough times," he told a crowd of about 100 party faithful at a Fredericton hotel on Wednesday.
"We've gone through two tough elections. But we've been through this before ... and I am convinced that we are going to be stronger than ever after our renewal process."
Gallant said it is time for a new approach to politics in the province and that starts with the renewal of the Liberal party.
"I think that we have to have transparency, I think we have to have a format where it can be inclusive, and I think we have to have accountability," Gallant said.
He said while others have talked about a new approach to politics, he's committed to seeing it happen.
Gallant failed to win the seat of Moncton East for the New Brunswick Liberals in the 2006 provincial election when he ran against then-premier Bernard Lord in the riding.
He is a former president of the student union at the University of Moncton.
During his speech Wednesday, Gallant said the province needs to invest in education, but he did not make any specific policy announcements.
He said he wants to hear suggestions from people across the province before coming out with policy.
So far, former health minister Mike Murphy and Belledune Mayor Nick Duivenvoorden are the only other declared candidates for the leadership.
Victor Boudreau has been acting Liberal leader since Shawn Graham stepped down in November 2010.
In the September 2010 election, Graham's government was soundly defeated, capturing 13 of the province's 55 ridings.