The striker collected his fifth championship after United defeated Aston Villa 3-0 at Old Trafford.
A Robin van Persie hat-trick - the second goal among the best scored at Old Trafford - propelled Alex Ferguson's side to victory in front of a jubilant home crowd.
And after the final whistle, Rooney believed the squad and manager had more of a desire to go out and win their 20th title after neighbours Manchester City had won it in such dramatic style last season.
"It's what we worked all year for and we've fully deserved it," Rooney told Sky Sports. "We won this game in the first half and it is a fantastic night for us.
"When you lose the title, it's hard to take and the way we did it wasn't a nice feeling last time so we've all dug in deep and all worked together and done fantastic to put ourselves in the position tonight to finish the job off.
"You know how football is so you never take anything for granted so we worked hard and thankfully now it's done.
"The manager has great desire and a winning mentality. We all buy into that and want to do well for the club."