The 1-0 victory over Wolverhampton Wanderers at Molineux on Tuesday evening meant Town achieved the feat with two games of the normal league season to go.
Wagner now takes his side to Birmingham City tomorrow afternoon (kick-off 3pm) before signing off at home to Cardiff City the following Sunday, May 7 (kick-off Noon).
Town then enter the excitement of a two-legged Play-Off semi-final for a chance to make the Wembley final on Monday, May 29 for the ultimate prize of promotion to the Barclays Premier League.
And the German boss believes whatever happens for the rest of this season, the club have made ‘a big jump’ forward that has taken everyone by surprise – including the club itself.
“We always wanted to make a step forward this season,” David Wagner reflected. “The Chairman didn’t want to tread water any longer.
“But I think we did more than one step but instead a big jump, one which would normally take two or three years for a club like Huddersfield Town to achieve.
“We have made a lot of good decisions throughout the football club, created a great atmosphere in the stadium and in the training ground.
“The players have so much self-belief and trust in what they are doing and this feeling has helped them to perform consistently well at a high level."
But although Wagner admits his side have over-achieved this season, he insists it does not mean there will be any let-up for his side – regardless of the final outcome of this campaign.
“Getting into the Play-Offs is the biggest step and achievement for this football club for 45 years.
“But it doesn’t stop here - we are hungry and greedy for more."
Despite the over-achievements bringing about higher expectations for the club in the future, it is not something the Town boss is immediately worried about.
“My head and brain is not big enough to think about managing expectations next season when we are still in this one,” Wagner added.
“Maybe a few days after this season is over I will have a think about managing expectations.”