The Independents 4 Change TD Mick Wallace has been elected as an MEP for Ireland South.
He reached the quota and secured the third seat in the constituency following the distribution of votes from Sinn Féin's Liadh Ní Riada.
His surplus of more than 19,600 votes will now be distributed between the two remaining candidates.
Mick Wallace's Independents 4 Change colleague Clare Daly has already secured a seat in the Dublin European constituency.
The 19th count in Ireland South also saw the Green Party's Grace O'Sullivan overtake Fine Gael's Deirdre Clune in the number of votes.
Whoever takes the fourth seat will be able to take their seat as soon as the new European Parliament term begins.
However, the fifth and final successful candidate will only take their seat if and when Britain leaves the European Union.
While both O'Sullivan and Clune are now guaranteed a seat, the redistribution of the Wallace surplus will determine what order they take their seats in.
Green Party campaigner Ed Davitt said Senator O'Sullivan did 'better than expected' in the latest count.
— Ed Davitt (@davitter) June 5, 2019
Earlier, Senator O'Sullivan said: "Because the pattern over the last week wasn't very clear how it was being distributed, it's anyone's call as to who will get that fourth seat and who will get that fifth".
The count in Ireland South resumed yesterday, after Ms Ní Riada conceded during the initial stages of what was set to be a full recount.
There had only been around 300 votes between the Sinn Féin and Green Party candidates.
Ms Ní Riada congratulated Senator O'Sullivan on her seat, adding: "I am happy that the democratic process has delivered the clarity we sought given that the initial difference was so tight."