Rooney's future at United was the subject of much speculation and uncertainty over the summer after Ferguson claimed towards the end of last season that the 27-year-old had asked to leave the club.
Though Ferguson has now retired as manager, his presence at Old Trafford as a director has reportedly kept a question mark hanging over Rooney's long-term future.
He was a target for Chelsea in the transfer window, but United stood firm and refused to sell the England international to their Premier League rivals.
Ferguson's successor David Moyes has been happy with Rooney's early-season form and labelled the forward 'world class' after he scored twice in Tuesday's 4-2 win over Bayer Leverkusen.
Rooney's brace in the UEFA Champions League took his tally to 200 goals for United and Ferguson is also happy with how his former player is performing.
"Wayne was fantastic," Ferguson told MUTV. "I'm pleased to see that. He's got his energy back, his purpose to attack.
"As a director, I'm delighted to see him back to how we remember him."
Ferguson added: "What is important and key to the team is if Vida (Nemanja Vidic) stays fit. With Van Persie and Rooney, there are forwards that can win games, Valencia's back to his best and it's amazing how a shirt number can affect a player.
"De Gea's maturing, Evra was normal and Carrick is continuing from last season. There were lots of plus points."
Ferguson has also defended Moyes after his fellow Scot came in for criticism following United's 1-0 defeat at Liverpool earlier this month.
Moyes had earlier enjoyed a 4-1 success at Swansea in his first Premier League game before a 2-0 victory over Crystal Palace last Saturday secured his first home win as United manager.
"I loved the Swansea game, enjoyed Saturday and Tuesday," continued Ferguson. "I enjoyed the Swansea game, United were terrific, but the Liverpool game was agony. I spoke to David about this after the Liverpool game.
"We've gone there over the years, 20-odd times, and played worse than that and won games, and I can't believe the criticism of United in that game.
"I thought David was right. They played well, could have done with a goal, but in the context of my experience of going to Liverpool, I can't remember when they hardly got in our box. I was frustrated with that because we deserved more."
The 71-year-old also remains convinced that he made the right decision to retire at the end of last season after over 26 years of unprecedented success as United boss.
He said of retirement: "I've enjoyed it. Obviously some things you miss and some you don't. You miss the banter in the dressing room and the humour on the training pitch, and the relationships built up over long periods with so many of the coaching staff.
"Some things you don't miss - press conferences on a Friday played over and over again for the whole day.
"I've relaxed about retiring and I left at the right time. It was a great period of my life at United."
Ferguson also denied suggestions he may have had influence over referees during his career after former official Mark Halsey referred to having a "good relationship" with the ex-Red Devils manager.
He said the extent of his relationship with Halsey had been to support him during his battle with cancer, commenting: "I can't believe...obviously there is an Alex Ferguson element in his book, he thought was important.
"Most of the managers, particularly in the north west, supported him, and lots of players by the way, when he had the cancer, him and his wife, it was a terrible period for the lad and quite rightly the football fraternity got behind him and supported him.
"We gave him jerseys after jersey for the dinners he was having and of course a Manchester United strip figures greatly in these auctions, a signed strip from all the players."
Ferguson was no stranger to fallings out with officials during his time in the dugout, and added: "The laughable part for me was how I (supposedly) influenced the refereeing fraternity.
"This is a guy who has the worst record of any manager in the history of English football, fined £100,000 by them, suspended so many times, that's some influence, I must say. It's a little bit Walter Mitty."