Rooney's deflected first-half effort saw off a dogged Reading outfit, who worked hard but lacked the class to fashion an equaliser.
The Royals now look certainties for relegation, sliding seven points adrift of safety with one game fewer than United to save themselves, their decision to axe Brian McDermott akin to shuffling deck chairs on the Titanic.
Thirteen points will do it for Sir Alex Ferguson's men to clinch a record 20th championship - and given one of their remaining games is against nearest challengers Manchester City, they might not even need that.
Yet taking maximum advantage of City's defeat at 10-man Everton earlier in the day was not the biggest talking point.
For that revolved around Rio Ferdinand, who rolled back the years to turn in another marvellous performance, which included claiming the assist for Rooney's winner.
The will he-won't he debate over Ferdinand's international return may not be answered for certain until Monday night, when Hodgson's squad are due to report at St George's Park.
However, there can be no doubt why Hodgson has been willing to go back on all those previous indications that he had "moved on" from the 34-year-old.
Quite apart from the vast experience that would make Ferdinand such an unflappable presence in that vital World Cup qualifier in Montenegro on March 26, the former West Ham man also possesses an assurity in possession that few Premier League defenders of any nationality, let alone English, can match.
He created United's first chance for a start with an elegant crossfield pass to Ashley Young, which the winger controlled on the edge of the area before drilling a cross-shot just beyond Robin van Persie, and more importantly, the far post.
Ferdinand's next incursion was the crucial one.
Nipping in to intercept Garath McCleary's poor pass, Ferdinand advanced into the open space and nipped round a static Mikele Leigertwood before feeding Rooney just to his left.
The striker took aim and once his shot flicked off Alex Pearce, former Manchester City goalkeeper Stuart Taylor had no chance of keeping it out.
Ferdinand's part was acknowledged by the Stretford End though, along with a non-too-subtle hint that he should reject the chance to extend his 81-cap international career.
Either side of Rooney's goal, Danny Welbeck went close on a couple of occasions and Robin van Persie tried his luck from 20 yards.
These are not the most productive of times for the Dutchman though, who has now scored once in his last 10 games.
After being thrust into the spotlight following McDermott's controversial dismissal earlier in the week, Eamonn Dolan became the 15th manager, including caretakers, to face the Red Devils in their first Premier League game in charge.
Most have lost. And whilst Dolan was not quite accepting of his fate, he seemed to have settled on a policy of damage limitation despite Reading's position becoming even more perilous due to earlier triumphs for Southampton and Aston Villa.
Only once did the visitors truly threaten before the break, when Hal Robson-Kanu let fly with a shot David de Gea would not have reached if it had been on target.
They should have had a chance to equalise immediately after it though when Nemanja Vidic shoved Adrian Mariappa over inside the box. Reading appealed for what TV replays showed to be a clear foul but referee Lee Mason was unmoved.
United failed to profit from their good fortune, with Welbeck and Young going close either side of a wild effort from Van Persie that flew out from a throw-in.
Van Persie's loss of form seems to have crept up unnoticed. His free-scoring ways earlier in the season are a mere memory now, with Taylor repelling a well-struck free-kick to keep the former Arsenal man out.
Whilst Rooney did fire over from long-range, the hosts gave Reading enough hope to believe an equaliser was possible.
It did not come though. And as certain as it appears United will end the season champions, Reading looked destined the finish it in the Championship.