The manager watched on in a baseball cap as Chris Durkin and Taxiarchis Fountas struck late on, stunning an Orlando side which had led since the ninth minute after Junior Urso's sublime chipped finish.
Durkin fired DC level from close to the penalty spot in the first added minute after the regulation 90 was complete, finding the top-left corner with a first-time finish after meeting Ola Kamara's clever low cutback from the left wing.
A draw would have been a decent result for DC, which sits at the foot of the Eastern Conference, but it got even better as a superb goal won it. A volleyed cross from the left by Kimarni Smith was met 12 yards out by Fountas, and he deftly diverted the ball into the bottom-right corner. It was a team-leading 11th goal of the season for Fountas.
It meant that DC United won an MLS game after trailing at half-time for the first time since March 7 2020, when it did so against Inter Miami. That dismal 25-game barren run is over, with the Rooney impact already being felt.
The record goalscorer for Manchester United and England has joined DC – a team where he also had a two-season playing stint – after recently leaving English club Derby County.
Midfielder Ravel Morrison, recruited by Rooney, attempted 96 passes in the game, and that ranks as the highest total for a DC United player in MLS this season.
Orlando had not lost an away game in MLS when leading at half-time since September 22, 2019, the date it allowed a lead to slip against Houston Dynamo.