Sinn Fein leader Gerry Adams made a dramatic entry into Irish politics by heading the poll in Co. Louth, the constituency he moved to from his West Belfast home.
Adams gave up his Westminster seat in order to run in Louth.
"It's a big day for me and my family, because it was a very big political gamble to wrench myself away from West Belfast, and I am indebted to the people of West Belfast," Adams told the media.
"We went out in this election, we set out our stall very, very clearly," Adams said.
"I think the votes across the state show a significant amount of people support the position we have taken up."
Northern Ireland Deputy First Minister Martin McGuinness said he was delighted with the result.
"It's very heart-warming to be here and see that the people of Louth were able to see through all of that, all those who tried to undermine Gerry Adams' incredible contribution to peace in Ireland and to politics in Ireland," McGuinness said.
"To be in a position to be elected in the first count, to top the poll, is an incredible result."