Labour’s Willie Penrose has taken the final seat after six days of counting in the Longford-Westmeath constituency.
His victory means that the party has now achieved the minimum seven seats needed for Dáil speaking rights.
The 15th count also saw Peter Burke of Fine Gael winning the third seat.
Kevin 'Boxer' Moran of the Independent Alliance and Robert Troy of Fianna Fáil won the other two seats.
The result of this count may still be in some doubt however, after defeated Fine Gael candidate James Bannon said that the margin of his defeat is very narrow and he will take "careful advice" and "will make a decision on whether or not to pursue a legal option".
The results leave the final seat count of General Election 2016 as follows: Fine Gael 50, Fianna Fáil 44, Sinn Féin 23, Independents 17, Labour 7, AAA/PBP 6, Independent Alliance 6, Social Democrats 3, Green Party 2.
"It was a touch of Lazarus," he said after being elected.
"I got three runs of Lazarus this time.
"It just shows you the vagaries of the proportional representation system.
"I'm delighted to have secured it. It's the sixth time I've been elected. It's a great honour and privilege to represent the people.
"It's very important in the context of the Labour Party itself. I'm the seventh member and that's very important in terms of us, we are the oldest political party in the state, born in 1912. We have a very proud tradition."
Mr Penrose told RTÉ Radio: "To those who wanted to write us off prematurely or to those who predicted our demise, let this be a warning and a signal that we do not intend to die easily, we intend to reorganise and rebirth."
The Labour TD has been in the Dáil since the so-called "Spring Tide" of 1992.
He was appointed to a junior ministry dealing with housing in 2011 but stood down after six months over the closure of an army barracks in Mullingar. Two years later he rejoined the party ranks.
Mr Penrose defeated James Bannon of Fine Gael for one of the final seats in one of the closest fought contests in the 2016 election.
The knock-out blow was delivered at about 5.30am today at the count centre in St Dominic's community centre in Keenagh, Co Longford, dubbed the Siege of Keenagh by some of those who stuck with it to the bitter end.
Mr Penrose's victory ensures Labour's leader has valuable time to question the Taoiseach and Tánaiste in the Dáil, a precious bonus to help the party maintain a profile after its setback in the election.
Labour has gone from 37 seats to seven.
Mr Penrose, who took a phone call from party leader Joan Burton at 6.15am, said he was not interested in contesting a leadership race.