The former Manchester United manager has revealed he sold Beckham to Real Madrid in 2003 because he felt the former England captain had lost his focus.
But Beckham has no ill feelings toward the man who nurtured his career at Old Trafford.
Beckham, who was speaking to fans on his Facebook page at the launch of his new autobiography, said: "I'm not going to sit here and be negative about a man who gave me the chance to play for my boyhood team. That I'd always dreamt of playing for.
"For me, like I said, he gave me the chance to do that. He believed in me, he believed in the rest of the young lads that came through with us."
He joked: "Funny thing was, obviously I'm involved in the MLS and I'm involved in bringing my own franchise into the league and actually he was one of the first numbers that I was going to call to be manager, but I'm not so sure anymore. I'm not sure he'd accept.
"All joking aside, at the end of the day, I wouldn't be negative about Sir Alex Ferguson because he was the man that gave me the chance to live my dream."
Beckham is planning to set up his MLS franchise in Miami, although an ownership deal is yet to be agreed.
The 38-year-old admits he is relishing the challenge of setting up an American team following his successful playing career at Los Angeles Galaxy.
Beckham said: "When I signed my contract six, seven years ago, my manager Simon Fuller actually got a clause in the contract that enabled me to have a franchise at the end of my playing career and obviously now I've stopped playing.
"A year before we started looking around at different places. Miami was obviously one of them.
"We've looked at other places as well, but I'm excited about that. I'm passionate about it. I'm passionate about staying involved in football. An owner of a team is something I'm passionate about."
Beckham witnessed the growing popularity of the MLS during his six-year stay in California and expects the organisation to make more strides in the future.
"It's going to get better and bigger," he said.
"Since I moved there 11 to 12 teams have come into the league.
"I have seen stadiums built. I have seen the excitement of the people talking about soccer or football."