A 3-0 win over relegation-threatened Aston Villa on Monday night secured the 2012/13 Premier League crown thanks to a sensational Van Persie hat-trick at Old Trafford.
The success erases some of the memories of losing the title to derby rivals Manchester City on the final day of last season but Ferguson praised his own legacy after winning a remarkable 13th Premier League.
"You can go on and on about losing the title (last season)," Ferguson told Sky Sports after the win over Villa. "I think we have been second maybe five or six times in my time.
"We can think back to the last game at West Ham (in 1995). How we did not win was unbelievable. Last year, it was the last game of the season.
"At the end of the day, our consistency for the last 20 years has been unbelievable."
Van Persie, a £24million signing from Arsenal last summer, is widely considered to be a key factor in United's title win.
And Ferguson hailed the Dutchman, whose second goal was a contender for the best of the season after volleying a long Wayne Rooney pass.
Van Persie has now scored five times in his past three matches, which started with a penalty at Stoke City, since going on a two-month spell between February and April without a goal.
Ferguson said: "It was the goal of the Century, for me, a marvellous hit."
The Scot added: "He has been unbelievable. His form in the first six months was fantastic. He had that spell where he had not scored a goal. Like every striker, he had a dry spell.
"But when he scored that penalty, I thought, 'he is alive now'. Tonight, he was unbelievable, marvellous."
Ferguson added: "He has made a fantastic contribution to our season.
"In terms of impact he has as big as an impact as anyone I can imagine.
Cantona was an incredible impact player and I have been very, very lucky, I have had some fantastic strikers right through, probably 10 great strikers at the club.
"I think we had an expectation. His performance for Arsenal last year was sensational and I remember Arsene saying to me 'he's a better player than you think' when we concluded the deal and I think he was right.
"He's in his mature years and winning the league meant the world to him."
Ferguson insisted that the title triumph has given him fresh impetus to carry on.
Asked about his own future plans, Ferguson joked: "Look at me - it's taken 10 years off me today. It's these tablets, they're great!"
Ferguson also had a dig at Manchester City boss Roberto Mancini who had said the only difference between the two sides this season had been in "attitude".
The United boss added: "He's right in one respect - in the games between the two of us there has been nothing in it.
"But the rest of them we have been far better, we are a far better team than Manchester City in beating other teams. That's not recognised by him.
"When the two teams meet there's nothing in it, I agree with him in that respect. Apart from that stupid performance by us at Old Trafford which cost us the league last season, and we won't make that mistake again, the games have been close."
Ferguson also believes this squad of players stands equal with any of his sides of the past.
"We've won most of our games, drawn three, lost four, and the [van Persie] goal, all the great goals we've scored over the years, from David Beckham through Ole Gunnar Solskjaer, Eric Cantona, that goal has joined that. These players have joined the pedestal," he said.
"I think Rafael will eventually be comparable to Gary Neville; Jones, Ferdinand, Evans, Vidic are comparable to all the other centre-backs we have had.
"I'm not saying they are better but great players are great players and the nostalgia thing does play tricks with your mind."