120 minutes passed with barely a chance to speak of as both sides cancelled each other out, with the best opportunity of the match falling to Izzy Brown in the opening five minutes.
The match was preceded by an almost impeccably observed minute's silence for the victims of the Manchester attack a week previous, with football once again standing as one in the face of extremism.
The touching silence was followed by a spine-tingling roar from both ends of the stadium, with a party atmosphere forming around two sets of fans enjoying their day in a spotlight they surely hadn't expected at the beginning of the season.
Early chances go begging for Terriers
It was to Michael Hefele, the former striker turned centre-back, that the first good opportunity of the match fell in the opening minutes. After some nervous passing round the back by Reading, the Terriers won a free kick on the left flank.
Aaron Mooy planted it onto the German's head straight in front of goal, but he scuffed his header tamely wide.
Soon after, the Terriers had another golden opportunity after good work from Elias Kachunga in the Reading area. He picked out a pass across goal for Brown, but the Chelsea loanee appeared to see the ball late, diverting the ball wide from barely a yard out.
A good deal of the play in the opening quarter of the match came down Huddersfield's right wing, as Kachunga and Tommy Smith combined to good effect. Kachunga's good work brought a yellow card for Joey Van Den Berg and a promising free kick, but nobody met Mooy's low ball in from the right.
Promising first half fizzles out
Reading failed to create much of note in the opening half-hour, and save a Lewis Grabban effort which curled wide in the opening exchanges, their first chance came from a long-range free kick with 35 minutes played.
John Swift tested his luck with the ball in a central position but mis-hit his effort, which bounced twice on its way wide of the post.
That disappointing effort more or less saw the end of the action in a first half which petered out after a hugely promising start.
A tense and tactical affair saw to evenly matched sides going largely blow-for-blow with neither team truly having a stand-out player taking the game by the scruff of its neck to make the difference.
Second half brings flair but little end product
To the delight of both sets of fans, however, the second half started out in considerably more open fashion as both sides had their first shots on target within three minutes of the restart.
First, Chris Löwe saw a dipping drive from wide on the left fly safely into the hands of Ali Al-Habsi, before a smart low stop from Danny Ward denied Swift's effort from the edge of the area at the other end.
Reading seemed to decide between themselves that the spectacular was the best way to break down a stubborn Huddersfield defence.
Yann Kermorgant attempted an audacious hooked shot over the shoulder from a corner which drifted to the edge of the area, before Grabban looked to dink the ball over Ward with the outside of his right boot as he fought to get clear down the left.
As the half wore on, it began to resemble the previous 45 minutes once again, albeit with more attacking intent from both sides. There was plenty of hustle and bustle from both sets of players, but no defining moment of quality to set the teams apart.
Quaner and Gunter go close late on
With a quarter of an hour to play, Mooy's persistence down the right saw him with space to run into at the edge of the area. He drove inside and pulled the ball back for the onrushing substitute Collin Quaner, but the powerful German couldn't direct the ball goalwards.
Inside the final five minutes of normal time, there was bad news for Huddersfield as captain Smith was stretchered from the pitch after what had initially seemed an innocuous coming together at the edge of his own penalty area; the experienced Martin Cranie was the man tasked with replacing him.
Both sides seemed invigorated into a final push as seven minutes of stoppage time were announced, with Reading skipper Chris Gunter almost managing to steer an ambitious header across goal and into the far corner from McCleary's deep cross.
Then, at the other end, a breakdown in communications saw a promising Huddersfield attack break down as Brown failed to read Mooy's intentions, the on-loan Manchester City midfielder passing the ball straight out for a goal kick.
There was time in the final 60 seconds for both sides to have one last crack at glory. Swift dragged wide for Reading at one end, before Nakhi Wells drew a low save from Al-Habsi with the last kick of the 90.
Extra time brings no excitement
Rather than being spurred into life by the prospect of a penalty shoot-out, extra time was a continuation of the theme set by much of the match thus far.
There were half-chances, still - Brown flicked a corner towards goal, McCleary tried to force the issue from range on more than one occasion - but the two sides continued to cancel each other out, nullifying each other's strengths rather than amplifying their own.
To their endless credit, both sets of fans continued to respond to every attack as if it was the first ten minutes, claiming every ball and screaming for their teams at every request from the pitch.
The Huddersfield faithful were almost rewarded for their loyalty with 115 minutes played as a counter-attack from a Reading free kick saw the ball fall to number nine Wells some ten yards from goal.
With time and space to turn and shoot, he mis-kicked the ball and dragged his afford agonisingly wide, appearing to hurt himself in the process.
They went close again in the final second as Löwe's free kick from the right dropped just out of reach at the far post, with a penalty shoot-out a fitting end to a game of little quality.
Schindler strokes Terriers to the Premier League
In the end, it fittingly fell to one of Wagner's German imports, defender Schindler, to roll in the winning penalty after a shoot-out which had at first appeared to be going in the Royals' favour.
Liam Moore fired over for the Royals and Jordan Obita's spot-kick was saved by Ward, allowing Schindler to step up and fire the Terriers to glory.