Few could have foreseen the 28-year-old playing such an important role for the Red Devils after a summer in which his future had looked in doubt.
However, after Chelsea's overtures were rebuffed, the England forward has knuckled down and on Saturday helped United to a 3-1 Barclays Premier League victory at Fulham - their fourth straight win in all competitions.
Rooney played a key part in the success at Craven Cottage, providing an assist, a goal and energy that allowed him to take hold of the match when the hosts threatened.
The striker appears to be blossoming under Moyes' tutelage - a far cry from their well-documented fractious relationship at Goodison Park.
"He is a big leader in the team and desperate for the team to be successful," the Scot said. "Obviously, having a successful team helps him as well.
"He has got leadership qualities. He is a man when he is on the pitch.
"On Saturday, we felt young Adnan (Januzaj) needed to drop in so I had to pull him out for the last 15 minutes to make sure we didn't do anything stupid.
"He understands that and I think he is at an age now where he sees that as well."
Rooney's assist and goal at Craven Cottage bookended a whirlwind 13 minutes in the first half.
Antonio Valencia opened the scoring from the forward's pull back, with Robin van Persie netting before Rooney struck - a ruthlessness often lacking at United this season.
"We have had spells like that but we haven't scored the goals," Moyes said.
"I can think of two or three games very similar, where we have had that sort of play but not got the goals at the end of it.
"I think it has been coming in a way, and thankfully on Saturday we got them quite early on."
United are now slowly but surely quietening the naysayers, having gone unbeaten since losing at home to West Brom on September 28.
Moyes, though, admits he still finding his feet at Old Trafford and learning his players' strengths.
"I would have to say I need to see more," he said.
"The way it is, you don't always play them eight or nine games in a row because the squad means you can rotate them quite quickly.
"It takes a little bit longer to see that and we're still looking for some consistency in some areas, some positions and we will continue to look for that.
"I think whatever happens at Manchester United, you have a squad and have to use the squad.
"Whether you have consistency or see the ball, you still have to rotate the squad here.
"That is part of the job and maybe that is why Manchester United come stronger later in the season because they have not used their players so much earlier in the season."