Sinn Féin Dublin West councillor Paul Donnelly has out-polled Taoiseach Leo Varadkar in his constituency.
He was elected after the first count in Dublin West after receiving 12,456 votes.
The Fine Gael leader was just shy of the quota of 8,726 with 8,478 votes.
Speaking before the result was announced, Mr Donnelly told Jonathan Healy he did not expect to top the poll and that he is delighted at the performance of his party.
Mr Donnelly said: "We were fairly confident that we were going to be in the mix for a seat, but I don't think we expected that we would be up in the numbers that we have at the moment.
"It's really good and I'm delighted to hear right across the State that Sinn Féin have polled magnificently well.
"I suppose it's the message being sent to Fianna Fáil and Fine Gael that they have failed them, and they were looking for a change".
— NewstalkFM (@NewstalkFM) February 9, 2020
Mr Donnelly said his party will enter government only to make real change.
"Sinn Féin have a resounding mandate from the people to be in government - but I certainly believe that we will not be in government certainly until we can implement a really, really genuine change and make people's lives different".
Asked of the electorate has moved on from Sinn Féin's past, he said: "We presented a real alternative in terms of what a government would look like if it was lead by Sinn Féin - and that resonated with people".
"All I can say is that a massive amount if people have voted for Sinn Féin... and we are going to ensure that that mandate is respected".
Mr Donnelly is a member of Fingal County Council and has been involved in many community organisations.
He is also a founder member of the Blanchardstown Local Drugs Task Force and Mountview/Blakestown Neighbourhood Youth Project.
Main image: Paul Donnelly of Sinn Féin arriving at the Phibblestown Community Centre in Dublin West | Image: Eamonn Farrell/RollingNews.ie