Mr Fitzgerald, whose term as Lord Mayor finished two weeks ago, now joins fellow city councillors Dr John Sheehan and Kenneth O'Flynn in the contest to join poll-topper Billy Kelleher TD on the party's northside ticket.
The Knocknaheeny-based councillor has long been expected to throw his hat into the ring and said he made a final decision while consulting with family, friends and colleagues in the last fortnight.
He touted his success in three consecutive local elections and believes he can build on that again.
"In each election, I've increased my vote under difficult circumstances, especially in 2009," he said.
The party ran a one-candidate strategy in 2016, but Mr Fitzgerald said that it became apparent on the ground by the end of the campaign that there was support for another candidate.
"As the campaign went on, the interest in the party started to grow. The public was asking why there wasn't a second candidate," he said.
He said that some of his own supporters suggested that he should run.
Mr Fitzgerald is a community support worker with the HSE, working with the Knocknaheeny Youth Project. He said that his track record delivering for Knocknaheeny and Hollyhill speaks for itself, through his championing of the Knocknaheeny regeneration scheme.
"During the downturn, the only building sites in the city were in Knocknaheeny. That was built into the plan with the Troika, and I spoke about it to [former Finance Minister] Brian Lenihan on many occasions," he said.
Mr Fitzgerald said that his priorities if elected to the Dáil will be further regeneration of the northside, making housing more affordable, and tackling infrastructure like the long-discussed Northern Ring Road.
Fianna Fáil has not yet set a date for its Cork North Central convention, but it is expected to take place before the end of the summer. Although a strategy has not yet emerged, the party is expected to run two candidates.
Meanwhile, Fine Gael is expected to announce a second candidate today or tomorrow to run alongside Senator Colm Burke at the next election. An Taoiseach Leo Varadkar will attend a private fundraising lunch for the party in the Clayton Silver Springs on Friday, and the party wants its ticket finalised before. 2016 candidate Julie O'Leary and city councillor Joe Kavanagh are seen as the frontrunners for the nomination.