The Scot says the striker is a crucial player at Old Trafford and believes the England international's form is proof that he should have not been allowed to leave this summer
After a summer of uncertainty over his future at Old Trafford amid prolonged interest from Chelsea, Goal exclusively revealed in October that the England international is refusing to open talks over a new contract.
The 27-year-old has scored seven goals in 11 appearances for club and country this season, including two in England's final two World Cup qualifiers against Montenegro and Poland, and Moyes believes the forward's maturity is reflected in his performances.
"He's at the age in his career where he would be one of the main players and he's certainly a main player for Manchester United," Moyes told reporters.
"He takes responsibility, scores the goals that are required and he's done that from a young age.
"The age he is now, he's got that maturity and it shows in how he plays and the condition he is in with the way he is playing for club and country."
Moyes believes his decision to keep Rooney at United has been vindicated by the striker's displays but admits he found it difficult to prove some critics.
"I saw him like this on the first day of pre-season yet I had to keep telling everyone that was the case because the media thought it was different," said Moyes.
"I saw him in great form. He was in great fettle. His training was fantastic from day one.
"But people kept saying different things and I found it difficult to prove it different.
"You can see by his form and the goals he is scoring that what I was saying was right."