Few will forget that May Bank Holiday Monday in Wembley as Christopher Schindler stepped forward to dispatch the winning penalty in the Play-Off final.
And, just as Town fans thought life couldn't get any better, the German boss has so far ensured his side have adapted to top-flight life with aplomb.
Here Daniel Rushworth takes up the story, which stretches from April to the present day.
Town's patchy form continued, with the Terriers recording three wins, four loses and a draw in the month.
Despite the indifferent form, the German was confident his decision to rotate his squad during the games in April would pay dividends in the final reckoning.
The most important month in Town's recent history opened with a 3-0 loss at home to Cardiff City on the final day of the regular season.
It meant Town were drawn to play against South Yorkshire rivals Sheffield Wednesday in the Play-Off semi-finals.
Following a nail biting 0-0 draw at home in the first leg , the Terriers travelled to Hillsborough for a tense second-leg finale.
An uneventful period of extra time followed - meaning Town's destiny would ultimately be determined by a penalty shoot-out with keeper Danny Ward producing heroics to send Town into the Wembley final.
David Wagner's men were now one game away from making the impossible, possible with only Reading FC standing in their way.
Following a 0-0 draw after extra time, Wagner's men held their nerve in the shoot-out to reach the top flight for the first since 1972 .
Wild celebrations followed with thousands turning out in the town centre to celebrate the triumph - the fairy tale season was complete.
The Premier League fixtures were released on June 14 with the club's first signing FC Porto striker Laurent Depoitre announced on June 23nd - for a then club record fee believed to be in the region of £3.5m.
As Wagner penned a new two-year deal at the club on June 30, the club also broke their transfer record for a second time - this time on Aaron Mooy - the Australian signing a permanent deal from Manchester City for £8.5m.
Later the same day, the German boss signed goalkeeper Jonas Lossl from FSV Mainz 05 on a season-long loan deal with a view to a permanent deal.
The first day of the month saw all the aforementioned deals finalised – including another loan star Elias Kachunga completing his permanent transfer from Ingolstadt for £1.1m.
There was no let-up at the club though with the players returning from pre-season and more business being done.
Three more signings were made on July 4 - Tom Ince joining from Derby County for £7.5m, Danny Williams from Reading on a free transfer and on-loan star Kasey Palmer rejoining the club on a season-long loan deal from Chelsea.
The following day saw Beninese international striker Steve Mounié join from Montpellier for a club record fee of £11.5m.
Two days later, left-back Scott Malone joined the Terriers from Fulham for £3.5m and a busy few days for Wagner came to a end with the signing of Danish international defender Mathias 'Zanka' Jorgensen from FC Copenhagen for £3.5m.
Away wins against Accrington Stanley (1-0) and Bury (3-1) followed before a quick trip to Germany to play SV Sandhausen (3-2 defeat) and then clashes against Barnsley away (1-0 win) and Udinese at home (2-1 defeat).
Town fans were sent into dreamland on the opening day with a 3-0 victory away to Crystal Palace.
Record signing Steve Mounié was the star with his double sealing a comfortable win, following the Joel Ward's first half own goal.
This was quickly followed by a home victory against fellow new boys Newcastle United with Aaron Mooy scoring a brilliant individual goal, seeing Town briefly go joint top of the league.
A EFL second round tie against Rotherham United was next with the Terriers running out 2-1 winners with goals from Phillip Billing and Joe Lolley.
On the same day Wagner completed his 10th signing of the window when Abdelhamid Sabiri signing from FC Nurnberg for £1m.
Wagner's final two signings of the window quickly followed, with Florent Haderjonaj joining on a season-long loan from Ingolstadt and goalkeeper Rob Green signing on a free transfer after this contract was mutually terminated by Leeds United.
The month of August was rounded up by a hard-fought 0-0 draw at home to Southampton.
After an impressive start to their maiden Premier League campaign, Wagner's side was brought down to earth with a bang.
Depoitre's first Town goal in a 1-1 draw at home to Leicester City was the Terriers only successful strike for the entire month.
However, there were positive signs with a scoreless draw away at Burnley, with fans coming away from the game feeling Town should have earned all three points.
The international break didn't allow Wagner to work his magic and turn Town's fortunes around immediately, starting with a 2-0 away defeat at Swansea City.
But Town's fans wait for a third Premier League victory was well worth it, as Wagner masterminded a 2-1 victory over Manchester United.
Goals from Mooy and Depoitre were enough to earn a historic win but the side were unable to repeat the trick the following week away to Liverpool, losing 3-0.
Ahead of the third international break of the season, the Terriers signed off with another impressive three points against West Bromwich Albion on the eve of the second anniversary of David Wagner's appointment at the club.
Rajiv van La Parra's first-half wonder strike was enough, although Town had to hold on with ten men for half-an-hour as Christopher Schindler was harshly dismissed for a second-bookable offence.