Fianna Fail's Padraig O'Sullivan claimed the seat in the Cork North-Central by-election on the tenth count.
Mr O'Sullivan had been the early frontrunner, claiming 27.6% of the first preference votes and he never relinquished that lead.
He fills the seat vacated by party colleague Billy Kelleher earlier this year. Kelleher had been a TD in Cork North-Central for more than two decades before his election to the European Parliament.
O'Sullivan did not reach the quota of 12,784 but was elected once all other candidates were eliminated.
In the end, Mr O'Sullivan proved a strong magnet for Colm Burke's transfers, picking up 2976 votes.
It was described early in the day as "a good day for Fianna Fail" by party leader Micheal Martin who has backed O'Sullivan to represent the area well.
He joins a tradition that includes Jack Lynch in representing the Northside of the city.
"There is a massive tradition for Fianna Fail on the Northside of the city," Mr O'Sullivan said.
"Jack Lynch, Danny Wallace, Denis Lyons; we have had great stalwarts over the years and I am proud to join that lineage of politicians."
It has been a busy spell for O'Sullivan, a 35-year-old school teacher in Fermoy. He was re-elected to Cork County Council in May and has a nine-month-old child, Paidi Og, while he and wife Bernie are expecting their second next year.
The coming months show no signs of letting up and he is ready to get right back out knocking on doors, he added.
"We knew the way the ground was laid when the by-election was called," he said.
"That is what we can attribute the turnout to. People knew there was a General Election coming. I think people will get the opportunity to make their voice heard soon again. It's a great honour to be here but it is back out campaigning soon."
Sinn Féin's Thomas Gould came second, finishing ahead of Senator Colm Burke (Fine Gael).
Mr Gould started the day in third but proved very transfer friendly throughout the day to overtake Mr Burke.
Despite not claiming the seat, Mr Gould was positive about the result which, he said, sends a strong message ahead of the General Election in 2020.
"Today has been a very positive day. We had a bad local and Eiropean election," he said.
"We analysed what went wrong and we put our plan in place. The people of Cork North-Central came out and gave us their support.
"We are asking people to put their trust in us and a lot of them still believe in us that we can deliver."
Turnout was the story of the day, with just 30.2% of the electorate coming out to vote.
It hit many of the parties on the left quite hard, with Solidarity and others seeing a decline in their vote from 2016.
Labour's John Maher and the Green Party's Oliver Moran put in strong performances which, they say, will leave them in a strong position ahead of 2020.