The celebrations, which included a massive street party in Belfast city centre, lasted well into the night - but there was a noticeable spring in the step of dozens of fans waiting at Belfast City Airport to board a flight for Finland ahead of the next game on Sunday.
Glenda Johnston, from Carrickfergus in Co Antrim - who was married at Windsor Park five years ago and has not missed a game in almost a decade, said: "I actually cannot believe what happened last night.
"I am so happy. It means so much."
It is 30 years since Northern Ireland qualified for a major football tournament.
As gushing air stewardesses and burly security guards rushed to have their pictures taken with the players, one veteran squad member remarked: "How times have changed."
Captain Steven Davis, whose two goals helped secure a place in French finals, said the players were enjoying the limelight.
Speaking at the British Airways check-in desk, he admitted some squad members had only a few hours of sleep.
He said: "It hasn't really sunk in yet. It was an incredible night. We couldn't have asked for it to go any better. It is hard to put into words at this moment in time.
"We enjoyed last night -- that was important.
"For the boys that have been in the squad for a long time, there have been a lot of difficult times playing for Northern Ireland in terms of getting consistency of results. A few of the younger boys who have been in the squad for a short period of time have only really tasted success.
"It was important to enjoy last night and we did that."
Chants of "Green Army" rang out as supporters wearing Northern Ireland football tops and waving French tricolours reflected on the game with glee.
Stewart McDonald, from Ballymena - who was at Windsor Park, said: "We are absolutely delighted for this country. The fans deserve it, they have been through so much.
"There were years when we just couldn't score and now we are qualified for the Euros - it is amazing.
"The celebrations last night were unreal. The police had part of the city centre sealed off and let the fans have a good party - it was a great night."
Fermanagh man Nigel Tilson, who regrets not going to the 1986 Mexico World Cup, said he was ecstatic with their win.
He said: "I have been waiting for 30 years for this.
"I think Helsinki it is going to be one big party."
Jason Stewart, from Co Antrim, was also among the crowds of fans flying to Helsinki for Sunday's match.
"The atmosphere last night, before, during and after the game was absolutely brilliant," he said. " I have never seen so many happy people - everybody was singing and dancing. I didn't want to go home to be honest.
"I couldn't not go to France. I'll definitely be there."
Northern Ireland's historic win has been lauded by some of the country's most famous sports stars.
Golfer Rory McIlroy, who was in the stands at Windsor Park, hailed it as a "great night for football".
Referring to the host nation for the 2016 championships, he tweeted: "Anyone for France next year?", before adding: "Unbelievable result for the republic too! Great night for the island of Ireland, north and south. Hopefully see both teams in France next yr."
World champion boxer Carl Frampton, who was also cheering on from the south Belfast stadium sidelines, said the players had made him feel proud of home.
Meanwhile, Prime Minister David Cameron took to Twitter to convey congratulations.
He said: "Huge congratulations to Northern Ireland on qualifying for the European Championships for the first time."
Democratic Unionist first minister Peter Robinson said: "Tremendous result and achievement. Huge congratulations to Michael O'Neill and team. Great night for Northern Ireland."
Sinn Fein deputy first minister Martin McGuinness tweeted: "Incredible night for Irish football, congrats Martin and Michael O'Neill (managers) & both teams. Beating the world champions in Dublin so amazing."
Northern Ireland Secretary Theresa Villiers also praised the team.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? firstname.lastname@example.org