Michael D Higgins has been re-elected as Irish president after receiving 56% of the country's election vote.
Businessman Peter Casey came second with 23.1%, while none of the other four candidates polled more than 10%.
Sinn Féin leader Mary Lou McDonald said she was "disappointed", but felt it was wrong for Fianna Fáil and Fine Gael to "sit on the sidelines" in the election.
Voters also supported the proposal to remove blasphemy as an offence from the Constitution, with 64.85% voting yes.
Mr Higgins, the first incumbent in 50 years to face a challenge in his bid for a second term, won with 822,566 votes.
Londonderry businessman Peter Casey took significantly more votes than the final opinion polls of the campaign had predicted. His final tally was 342,727.
Sinn Féin MEP Liadh Ni Riada got 93,987 votes - 6.4% of the total votes polled.
"I am not sorry that we had an election - I think it was wrong for Fianna Fáil and Fine Gael to sit on the sidelines," Ms McDonald told the BBC's Sunday Politics programme.
"We decided to challenge in the election - the other parties didn't."
She added: "I think my leadership would have rightly been called into question if I fell in line with Micheál Martin and Leo Varadkar.
"Of course I'm disappointed. I would have liked a better showing for Liadh [Ni Riada]but that was not to be.
"You learn from every contest. You learn from every encounter that you have with the electorate and we'll certainly learn from this."
Irish Presidential Election result
Valid votes cast: 1,473,900
- Michael D Higgins 822,566
- Peter Casey 342,727
- Seán Gallagher 94,514
- Liadh Ní Riada 93,987
- Joan Freeman 87,908
- Gavin Duffy 32,198
The result was confirmed at a declaration at Dublin Castle on Saturday evening.
Speaking after his win, Mr Higgins said he accepted his mandate with "humility, determination and excitement".
"People are interested in ideas that are sincere and constructive," he said.
"For words matter, words can hurt, words can heal, words can empower, words can divide.
"And the words and ideas I have used in this campaign reflect a vision for Ireland based on four strands.
"Equal and together, strong sustainable communities, sharing history - shaping the future and Ireland's voice matters."
Taking to the podium after Mr Higgins, second-placed Mr Casey said the last time he had stood in an election to the Irish Senate he got just 14 votes.
"Somebody worked it out there - it's about 23,000 per cent improvement," he joked.
Sinn Féin MEP Liadh Ni Riada said she hoped it was the last Irish presidential election in which people in Northern Ireland could not vote.
Turnout was reported to be low in many areas of the country.
More than 3.2 million people were eligible to cast their ballots in the election and referendum.
Taoiseach (Irish Prime Minister) Leo Varadkar congratulated Mr Higgins on his predicted win on Saturday morning.
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The president is Ireland's "first citizen", but has limited power - the role is mainly symbolic and he or she cannot get involved in daily politics.
Voters received two ballot papers at polling stations on Friday.
They were given a white ballot paper for the presidential election and a green ballot paper for the referendum on blasphemy.
Many were unaware there was such an offence until a member of the public referred controversial remarks made by the actor and writer Stephen Fry on an RTÉ programme to gardai (Irish police).
The investigation was dropped last year, reportedly because officers could not find anyone who was offended.