Newport County beat Wrexham to return to the Football League after a 25 year absence in the all-Wales play-off final at Wembley.
With the game looking to be heading for extra time, two goals in the last four minutes won the Conference play-off final.
The match has been called "a million pound game" beforehand.
County manager Justin Edinburgh paid tribute to the fans, saying: "This is for them."
A tense match was decided with goals from Christian Jolley (84) and substitute Aaron O'Connor in injury time
The original Newport County lost its league place in 1988 and was wound up the following year.
The club was reformed four divisions below the Football League but was "exiled" to playing in Gloucestershire until the mid-1990s.
It was a long journey back up the non-league pyramid, which saw in recent years the arrival of a millionaire chairman and a move to play matches at the Rodney Parade rugby ground near the city centre.
Congratulations started pouring, as celebrations were under way at Wembley.
First Minister Carwyn Jones said: "My sincere congratulations go to Newport County on their promotion back into the Football League.
"Bad luck to Wrexham, who just missed out on a second triumph at Wembley in recent weeks.:
"With Swansea City winning the League Cup, Cardiff City joining the Swans in the Premiership, Wrexham winning the FA Trophy, our very own Gareth Bale now considered as one of the best footballers in the world, and Newport County reaching the Football League - this has been a truly fantastic year for Welsh football."
The club's chairman, Bristol-born Les Scadding, a £45.5m EuroMillions winner, said it was a "dream" and paid tribute to those who had helped the club on its long road back.
"We've come from a relatively low point but came back and showed everyone we are a League side.
"It was a hard time: Hats off to those people - they were exiles, they didn't have a ground, and this is where we are - that's dedication."
Newport captain David Pipe told BBC Radio Wales: "Words can't describe it - I'm proud of my team, of myself, the management here, all those here and all those at home who couldn't afford it.
"I'm glad we were underdogs - we've proved everyone wrong."
Local AM William Graham called it an "incredible result," while former AM Lord German said on Twitter: "Up the Port. Back in business and the league. Fantastic result at Wembley".
Before the match, Newport County chief executive Dave Boddy called it "a million pound game" and the "biggest prize in football" outside the Champiionship.
"County has missed the Football League status and after a great season are just 90 minutes away from making it everybody's dream come true," he said.
"It's great for Welsh football for it to be an all Welsh final - it's a headliner's dream come true, let's hope that it's us leading those headlines."
Newport West MP Paul Flynn told BBC Radio Wales: "It's been a terrible recent history, particularly in the late 1980s, when we went out of business altogether and then our home ground was 50 miles away. It's a great tribute to all those who persisted with their loyalty to the club."
Wrexham fans made up around 10,000 of the 16,000 crowd, with the match coming only six weeks after the club made its first trip to Wembley, winning the FA Trophy by beating Grimsby Town on penalties.
Wrexham, the oldest club in Wales, was relegated from the Football League five years ago but after a difficult decade, was taken over by the Wrexham Supporters' Trust in 2011.
Before the match, Wrexham AM Lesley Griffiths said: "It's been a fantastic season for Welsh football across the board. So many people were devastated when Wrexham went out of the league, I was at the match at Hereford the night it happened."
"I went to my first match as a birthday treat in 1972. There's a feel-good aspect in the town and it's important we get back into the league."