Reading sealed promotion to the top flight for the first time in their history following a 1-1 draw at Leicester on Saturday.
Leicester took a deserved lead against a lacklustre Reading with Iain Hume's powerful finish after being set up by Matty Fryatt.
The Foxes' Joey Gudjonsson then struck a post from a free-kick.
But a Kevin Doyle close-range header earned Reading a point and Leeds and Watford's failure to win ensured Reading's place in the Premiership.
Steve Coppell's side went into the game knowing only a win would guarantee them promotion.
But with Leeds and Watford dropping points Reading would have been promoted even with a defeat.
Leicester made the better start in a scrappy opening which suggested the occasion may have got to Reading.
Hume got behind the Reading defence but saw his shot from a tight angle saved by Hahnemann.
The big American keeper then produced an acrobatic save to deny Fryatt.
Reading's sluggish display showed on the bench where manager Steve Coppell and his coaching staff became very animated.
It was no great surprise when Leicester took a deserved lead, with Fryatt setting up Hume for a thumping finish from just inside the penalty area.
Reading offered little threat in the first half and they might have gone further behind when Gudjonsson struck the post with a free-kick.
The Championship leaders mustered a shot in the second half when Bobby Convey saw his effort saved by Paul Henderson.
Leicester displayed the confidence that had seen them win their previous three Championship matches to claw clear of the relegation dogfight.
Gudjonsson illustrated that confidence with an outrageous attempt from all of 45 yards which Hahnemann saved with his legs.
But the Royals showed good spirit to rally and a James Harper corner was flicked on by Ivar Ingimarsson for Doyle to ghost in to head the equalizer from six yards out for his 16th of the season.
The Royals created another bit of history by becoming the earliest side to clinch promotion to the top flight.