Former United manager Ferguson revealed the England international handed in a transfer request at the end of last season before retiring from his post at Old Trafford after 27 trophy-laden years in charge.
This was reported to be a major factor behind Rooney agitating for a transfer away from the Premier League champions in the close-season, but United resolved to keep him and the striker has responded with a series of impressive performances.
And Ferguson has lauded Rooney's early-season form, particularly his showing against Bayer Leverkusen in the UEFA Champions League on Tuesday, where he scored twice to reach the milestone of 200 goals for United.
"I thought Wayne's performance was fantastic on Tuesday," the Scot told MUTV. "I was pleased to see that.
"He's got his energy back, his determination and his purpose to attack players.
"It was very encouraging for me and, being a director, I'm delighted to see that. He's back to the way we always remember him."
The 71-year-old also praised his successor David Moyes' start at the club, and admitted the recent 1-0 defeat away to Liverpool had been "agony" for him to watch.
"I loved the Swansea game, I loved Saturday (when United beat Crystal Palace 2-0), I loved Tuesday," Ferguson continued. "I thought they played terrific on Tuesday night. The Swansea game, terrific. The Liverpool game? Agony.
"I spoke to David Moyes about this after the Liverpool game. We'd gone there over the years, 20-odd times over the years, and we've played worse than that and won.
"And I can't believe the criticism United are getting. I thought that David was right - I thought they did play well. Yes, they could have done with a goal, but in the context of my experience of going to Liverpool over there - they hardly got in our box.
"So I was a bit frustrated with that game, because I thought they deserved better, I thought they deserved more, but they won well against Crystal Palace, a difficult game."
