'Keane best captain I ever played under'
Beckham backs former United team-mate as he refutes controversial claims in Fergie's book
Ferguson said that Keane had lost the respect of the dressing-room after he made a withering attack on some of his team-mates in an interview with MUTV that was never broadcast.
Beckham had moved on from Old Trafford at that point but stressed that Keane was always a positive force who inspired up-and-coming players to follow his path.
"For me, Roy Keane is the best captain I've ever played under," he said. "He had two career-threatening injuries and battled back from both of them. That set the example for us young kids and so did the way he worked so hard in training and on the pitch."
Keane came out in support of Beckham in the fall-out from Ferguson's book release, arguing that the Scot was wrong to single out players who had won trophies for him.
The retired manager had criticised the Englishman's celebrity lifestyle.
Responding for the first time to Ferguson's observations, Beckham rejected the claims that he came to consider himself "bigger than the club".
Beckham said: "I think if you speak to players I played with – players like Roy Keane, Zinedine Zidane, Ronaldo, Roberto Carlos and Raul – they will tell you my career was all about hard work.
"I think the manager (Ferguson) will as well."
Launching his own far less explosive autobiography, Beckham said he was only "kind of joking" when he revealed that he had been planning to offer Ferguson, who is 71, the chance to be manager the former United player's proposed new MLS team, which is likely to be based in Miami.
When asked by interviewer Jake Humphrey if Ferguson had broken a golden rule by publishing stories from within the dressing-room, especially given the Scot's desire to keep all such matters secret during his United career, Beckham replied: "Well, yeah, apparently they (dressing-room stories) do (come out).
"I am excited about my book; I wish him good luck with his. I won't be negative about Alex Ferguson because he gave me the chance to live my dream.
"He gave me the chance to do that. He believed in me and believed in the rest of the young lads who came through this with us. I was lucky to play under Alex Ferguson for 12 years and he's truly the best."
Beckham's decision to leave United for Real Madrid in 2003 was also criticised by Ferguson, who claimed that the midfielder's representatives had been in contact with the Spanish club long before his eventual £24.5m move.
The transfer to Madrid ended a 14-year spell at Old Trafford and Beckham said it proved so painful that he could not bring himself to watch his old club.
"When I joined Manchester United I never wanted to leave them. When they told me they were going to sell me was the first time I spoke to Real Madrid," he said.
"I knew my dream was over and I had to speak to another team. I couldn't watch United for two years. I was that gutted. It was that difficult to leave."
Beckham confirmed that he was determined to pursue his dream of taking over a club in America, after enhancing his superstar status even further during his spell with Los Angeles Galaxy.
The 38-year-old is still awaiting MLS approval after declaring an interest in owning a team in Miami, but he insisted he had no plans to manage.
"Being an owner of a team is something I feel passionate about. It has to excite me, management and coaching – I love coaching kids, my own kids and other kids – but managing is not something that floats my boat.
"I will be a dedicated owner. When I get involved in something, I am involved 100pc and it will be something I am proud of. Miami excites me because the people there are so excitable. They are ready for a football team."
Beckham also said he would attend the World Cup in Brazil next year and conceded that it had been difficult to adjust to retirement, after hanging up his boots at the end of last season.
"I had a moment a few months ago where I found it difficult to come to terms with not playing any more – a moment in Paris when I was on the plane working on a new project and I suddenly felt that jump from being a footballer into business.
"I've been busier in the last five months than ever before.
"I have that work ethic. Whether it's achieving success as a footballer, or in business."
In contrast to Ferguson making public appearances to promote his book, Beckham publicised his latest tome in a rather less exhausting manner, spending a couple of hours on Facebook engaging in electronic conversation with his fans, while signing his name on a few dozen selected virtual walls.
Ferguson may have spent much of the past week questioning his former charge's relentless pursuit of celebrity, but yesterday showed the rewards of such labour.
For a football man like Ferguson, Beckham's move from Real Madrid to Los Angeles Galaxy in 2007 was seemingly inexplicable, seeking such a soft landing from the pinnacle was anathema.
Now, in Beckham's retirement, we can see the logic of the move. If you are going to engage with celebrity, it is most fruitful to do so in the place it has greatest commercial value.
After five years living in Hollywood, Beckham has become a figure so internationally renowned that he operates on a level above traditional methods of book sales. He is a digital star for the digital age.
Indeed, that the pupil has surpassed the master in worldwide renown was further demonstrated when it was revealed this week that Beckham is poised to lead a new football franchise in the United States.
While Ferguson may have been invited to become a director at Manchester United, Beckham will be soon in a position where he can select a board of his own. (© Daily Telegraph, London)