The Royals have crept up on the blindside of Southampton and West Ham United, whom many had tipped to gain automatic promotion to the top flight.
Here, Sports Mole examines the key players and manager that made the success for the Berkshire club possible.
Adam Federici, goalkeeper
Reading have conceded just 37 goals this season, the fewest of any team in the whole of the Championship. A large reason behind that statistic has been the form of Australian international goalkeeper Federici. The 27-year-old has kept a total of 19 clean sheets this season and went on a run of 490 minutes without having his net breached earlier in the campaign. His penalty save during last week's 1-0 win over Brighton & Hove Albion underlined his importance to the Royals.
Ian Harte, left-back
Despite being 34 years old, full-back Harte has made a telling contribution for the Royals this season. His delivery from set plays has caused no end of problems for the opposition and his eye for a goal has proved vital at times. He kept his cool from the spot to help Reading claim a vital victory at West Ham United a fortnight ago. His Premier League experience with Leeds United could prove to be important next season.
Kaspars Gorkss, centre-back
Latvian defender Gorkss arrived at the Madejski Stadium at the start of the season as a replacement for fans favourite Matthew Mills, who left for Leicester City. Having helped Queens Park Rangers to gain promotion last season, the 30-year-old has put that experience to good use over the course of this season. His partnership with Alex Pearce is viewed by many as the reason why Reading have been so hard to break down, particularly at the Madejski.
Mikele Leigertwood, midfielder
There will have been few more important goals scored in Reading's history than the one that Leigertwood netted yesterday evening. The towering midfielder poked in the only goal of the match against Forest to rubberstamp his side's elevation back to the top flight. His form over the course of the season has received a number of plaudits, while he has also added five goals into the bargain.
Jason Roberts, striker
The experienced Roberts may only have arrived at Reading in January from Blackburn Rovers, but his impact on the whole squad has proved to be invaluable. The 34-year-old has found the net on six occasions from 16 outings, including one during last week's important win away at promotion rivals Southampton. His presence also appears to have brought out the best in fellow strikers Noel Hunt, Adam Le Fondre and Simon Church.
Brian McDermott, manager
The role that manager McDermott played in Reading's return to the Premier League has not gone unnoticed. In September, the boss was left with a squad that was second from bottom in the Championship and still suffering from last season's play-off final defeat to Swansea City. He also had to contend with the departure of leading goalscorer Shane Long and defender Mills. However, the addition of Roberts and Gorkss proved to be masterstrokes, while the use of some of the club's youth players was a hit with the supporters. Since January, McDermott has guided his side on a run of form that would see them lose just three times as promotion was guaranteed.