The Tigers did it the hard way, grinding out a 2-2 draw against npower Championship title winners Cardiff and then having to wait around for Watford's delayed match against Leeds to finish. But when news filtered through of a late winner for Leeds at Vicarage Road, the celebrations began in earnest at the KC Stadium with Allam and manager Steve Bruce leading the way.
"It was fantastic, one of the proudest days of my life," the Egyptian told BBC Radio 5 Live's Sportsweek programme.
"It was very stressful but at the same time, when we had four or five minutes left, Watford needed to score two goals to be promoted so that gave us a bit of comfort."
City return to the top flight after a three-year absence and Allam revealed it has come at a personal cost, but one he feels was necessary.
"Not only has the club been promoted but we've come through administration," he said.
"I bought the club in December 2010 four days before the winding up, so it was a case of saving the club, And in two and a half years of my ownership, we've gone from what would have been bankruptcy to the Premier League.
"To save the club from bankruptcy is what I call dead money, money I would have saved by waiting four days to buy the club from the receivers.
"I would have saved £27million in money owed to the taxman, who enforced the winding-up order, and two banks.
"But then the club would have lost 10 points, they would have been relegated and this would have cost more and I didn't want this, for the community to be deprived of good quality football. So I signed a contract knowing that I'm throwing away ?27million for the sake of staying in the Championship."