Ferguson will step down from his role as Manchester United manager at the end of this season, the Barclays Premier League champions announced.
Charlton was one of the United directors who appointed Ferguson in 1987.
The Red Devils boss has since gone on to win 13 Barclays Premier League titles - a feat that Charlton was quick to praise.
"He is such a fantastic manager. Everything he has done has been fantastic," said Charlton at the launch for the Royal Mail's Football Heroes Special Stamps.
"He is a sensational person in every form and I am really delighted for him.
"I am a director but I hardly do anything because we are winning all the time and it is all down to Sir Alex Ferguson.
"He would get up in the middle of the night and travel 300 miles if he thought there was a school boy that he could sign.
"He loves the game and we at the club have had nothing to do really."
- Sports & Recreation
- Sir Alex Ferguson
- Manchester United