The Terriers booked their place in the Premier League via a dramatic penalty shoot-out triumph over Reading at Wembley.
Despite missing their second spot-kick through Michael Hefele, Town prevailed 4-3 thanks to a save by semi-final hero Danny Ward and Christopher Schindler then converting the club’s fifth and final penalty.
“Huddersfield Town are part of the Premier League,” said German Wagner. “That makes me very happy.
“The last time this club was in the top division was 45 years ago. The people who can remember that time are very, very old. So, this is a big, big achievement.
“I am so happy and proud of my players. I am happy for the whole town. And especially the chairman (Dean Hoyle), who backed nearly all of my ideas – even when he thought maybe some were ridiculous.
“He just said, ‘Come on, let’s do this’. Now, we have done it. Our message all season is that there are no limits and we are now in the Premier League.
“The players have become legends. I said to the players before the play-offs, ‘You are heroes, what you have done in the league in this unbelievable season makes you heroes’.
“But I challenged them to become legends. They have taken that and are now, for sure, legends.
“Everyone will remember this group of players and what they have done, what a small budget they did it with and that the success was deserved; it was not a fluke.”
Town’s shoot-out triumph was their sixth in nine appearances in the play-offs, comfortably a record with no other club having won more than once on penalties.
It was also Huddersfield’s third in a final – and, like 2004 (Division Three) and 2012 (League One) it came after a goalless draw.
Wagner added: “I said to the boys before the shoot-out, ‘Listen, boys, it is the easiest thing to put the ball into the net from 12 yards – now after 10 months you have the opportunity to get in the Premier League by putting the ball in the net’.
“They put their hands up. I was pretty surprised when Schindy came to stand beside me and said he wanted to take the fifth penalty.
“I thought, ‘Okay’. But he was totally confident. I had Kasey (Palmer) in my head, but he was so confident I let him.
“When Michael missed, I just thought, ‘Wardy has to save one’.
“We have experience of penalties after the semi-final and I felt we deserved to win over the 120 minutes, we had the better chances.”
Wagner rightly wanted to bask in the glory of what Huddersfield have achieved last night, but he realises that attention has to turn quickly to next season.
Loanees Ward, Aaron Mooy, Izzy Brown and Kasey Palmer will all return to their parent clubs now the season is over.
Reinforcements will also have to be brought in to strengthen Town, who have made history as the only club to win promotion to the top flight via the play-offs despite having a minus goal difference in the regular season.
“I have a lot of calls to make, to be honest,” he said when asked about this summer’s recruitment.
“Maybe this is why I can’t get my head around this.
“I know how much work I now have to do.
“Of course, I have thought about the summer. But, the closer we got to the play-offs, it went to the back of my mind.
“I had to focus on Sheffield and then Reading. We were in the play-offs two or three weeks before the end of the season and I had to think about those games.
“I hope to keep it that way until at least Tuesday morning. I want to enjoy this. We need to celebrate what we have done.
“I only want to think about what we have achieved. There will be enough time to deal with what is in front of us.”
Pressed on his loanees and whether promotion will make it possible to bring back Mooy, Ward et al, Wagner indicated he does want to hold on to the players that have made history by making the Terriers the 49th club to play in the Premier League.
“I will speak with Jurgen (Klopp, Liverpool manager), for sure,” he added. “Not just about Danny but about the Premier League. But, give me time to get my head around this.”
On making history by taking up the Terriers, tipped by the bookmakers to struggle rather than challenge for promotion this season, Wagner added: “I am so happy we have proven that experience is not everything, especially here in England.
“Since I arrived, I was told I had no experience of English football, no experience of the league, no experience of not having a winter break and no experience of the play-offs. Experience is important, but if you have passion and desire, you can match it. We brought this fairytale to an unbelievably happy ending.
“We had so many setbacks and problems, especially because we didn’t have the biggest squad. But we ignored everything around us and trusted in ourselves. I am so happy it came to a happy end.”
Match report plus more pictures and reaction from Wembley: Pages 20 and 21