Rooney was unhappy at Old Trafford last season under Sir Alex Ferguson and at one point in the summer he appeared set for a move to Chelsea.
But the striker is now settled once again, and he hands much of the credit for that to Moyes.
The 28-year-old told the Sunday Mirror: "David Moyes' influence on me signing the new contract was absolutely massive.
"Certain issues did arise last season that I wasn't happy about. But out of respect to Sir Alex Ferguson I won't talk about what went on because as far as I'm concerned it's all in the past.
"When David Moyes took over he made it clear to me straight away that he wanted to draw a line under last season. And the key thing was when he assured me that he had total belief in me.
"Just as important, he also told me things that I probably didn't want to hear. He told me I had lost something from my game and that I needed to get back to basics."
Reports suggested Rooney's decision to sign a new contract last month was due in part to having been given privileged access to the club's transfer plans.
But the player denied asking for any say on the club's spending policy.
"I want to be clear about this: I have never asked the club for any input about transfers," Rooney said. "To suggest otherwise is crazy.
"Who we buy and sell is nothing to do with me. It never has been and it never will. David Moyes is the manager and decisions like that are for him to make."