"Wayne Rooney is not for sale. He's a Manchester United player and will remain a Manchester United player. Wayne won't be sold by Manchester United," the former Everton boss said.
Moyes, however, refused to say whether Rooney had expressed a desire to stay.
Ferguson said the 27-year-old striker had asked to leave at the end of last season - although Rooney is believed to contest Ferguson's suggestion he wanted to quit United.
Moyes explained he had spoken to Rooney, who has been linked with Arsenal and Chelsea, "several times" since being appointed.
"Whatever happened before has gone now," insisted the new United boss.
"We are working together now. I have seen a glint in his eye, he looks happy and looks as if he is going to knuckle down."
Moyes said Rooney's meeting with Ferguson "was a private meeting between two people".
"I was not privy to it," added Moyes. "I don't know what those two gentlemen said.
That conversation was private and as far as I am concerned I'm looking forward to working with Wayne."
And Moyes declared all his efforts were now going into improving Rooney's condition and form for club and country, with the player hoping to figure for England at the World Cup in Brazil next summer.
The Scot added: "We are working and trying everything to get Wayne to the level where everybody can benefit. I can tell you categorically Wayne is training fantastically well."
United captain Nemanja Vidic, sitting alongside Moyes at his introductory news conference, added: "Wayne has trained really well and is in the best shape for the last five years."
Moyes refused to be drawn on transfer moves for United old boy Cristiano Ronaldo and Everton's Leighton Baines after having a £12m bid rejected for the England left-back.
Moyes said: "I will never speak about players at other clubs. I think it's wrong. But this club is always interested in the best players."
I think Rooney should stay and retire at Manchester United. Just like Scholes and Giggs. I can't imagine him wearing other club's jersey, He is destined to be in Manchester United. :)
Rooney to stay!