(CNN) -- Alex Ferguson looks like an old-school football manager. Renowned for his infamous "hairdryer" blasts at under-performing players, he has the well-worn visage you associate with huge stress levels and his admitted love for red wine.
But the 69-year-old is much more than his gruff, often intimidating public persona, according to a man who has seen the Scot transform Manchester United's fortunes in the past quarter of a century.
"He was far deeper than that, more intelligent, more widely read, and he had a very clear idea of the modern game, the modern player and what the modern player needed to do," Ferguson's former adversary at Leeds, Howard Wilkinson, told CNN.
Ferguson is a tough post-match assignment for any television interviewer and has become adept at using the media in his battles with contemporaries such as Arsene Wenger and Rafael Benitez.
"He's nothing like the person you see after the game, or interviewed. The only thing that's true about him in those situations is his sincerity and his desire to make sure that he gets his point of view across," said Wilkinson, who in 1992 was the last English manager to win the domestic league title.
"He's become one of the best. Sometimes he hasn't got the credit for it, where sometimes other people have. I think his use of the media has yet to be bettered."
Ferguson arrived at Manchester United in 1986, flush from his incredible success at Scottish football club Aberdeen, and he was disappointed by what he found.
Appointed to replace Ron Atkinson on November 6, he inherited a squad of big-name internationals, a notorious drinking culture -- and the high expectations of a major club that had not won a league title in 19 years.
He, on the other hand, had taken Aberdeen to three Scottish titles, five domestic cups and -- most impressive of all -- a European Cup Winners' Cup final triumph against the mighty Real Madrid in 1983.
"He came into a Manchester United which, he's said many times, surprised him -- it was a disappointing surprise," Wilkinson said.
"He told me a couple of weeks after he'd been there ... he got the players together on a Monday morning, and the summary of his conversation was, 'Listen, fellas, you're going to have to change, because I am not going to change.'
"What he inherited, he saw the potential but perhaps at that point hadn't realized how much he was going to have to do. In the early years it was difficult, but fortunately -- thanks to Matt Busby and one or two others at the club -- people had patience.
"Not only patience but also they had foresight. They realized they had a jewel in their hands."
That patience has paid off, as Ferguson has transformed United ahead of his 25th anniversary at the club this weekend.
He can look proudly back upon 12 Premier League titles -- last season's was an English-record 19th for United -- plus two Champions League crowns, five FA Cups, four League Cups and a European Cup Winners' Cup.
But, if he had been employed in these cut-throat days, Ferguson may not have lasted past his first five years in charge.
It was widely speculated that he would be sacked if United lost to Nottingham Forest in an FA Cup tie in the 1989-90 season, but his team won that match and went on to clinch his first silverware at the club after a replayed final against Crystal Palace.
Wilkinson, however, believes Ferguson's turning point came at that fateful team meeting years earlier, and everything else flowed from there.
"He walked out of that gym, and it was the beginning. Clearly, he didn't win all the battles, but he won the war," said Wilkinson, now chairman of the League Managers' Association.
He credits Ferguson, a former union steward in the Glasgow shipyards, as one of the first in the line of modern managers who believe in high physical standards and a scientific approach.
"There was a drinking culture at a few clubs, and he and I shared many common values, and we both recognized that if you want to get the best out of your body as an athlete, then you couldn't keep abusing it," Wilkinson said.
"Changing culture at a place and changing behavior is the mark of a great leader. He's been there 25 years, and he's changed it permanently. That's what leadership's about."
Ferguson has a well-known love of racehorses -- he sued former United shareholder John Magnier over stud rights of a horse in 2003 -- but Wilkinson said his charity work is not so widely appreciated.
"He does go to great lengths to help those not as lucky as he is," Wilkinson said. "He travels here, there and everywhere for charities. ... He's got his own charitable trust.
"I know that he is very good with young people who are starting out. He reads their letters and gives them far more consideration than others, because he recognizes the need to give youngsters that help."
After winning the first staging of the new Premiership format in 1993 to end United's long wait for the title, Ferguson famously introduced a new generation of young players at United, including David Beckham and Ryan Giggs; the latter he persuaded not to sign for rivals Manchester City as a teenager, and he is still at the club.
He had also invested wisely in signing Eric Cantona from Leeds and midfield warrior Roy Keane from Nottingham Forest, both of whom had a major influence in United's new glory years.
Keane believes Fergie's hunger to succeed is what has kept him at the United helm for so long, despite an aborted announcement that he intended to retire at the end of the 2001-02 season.
"Hunger. It's as simple as that," the Irishman told CNN. "In football some players get a new contract, teams win a trophy, and you never hear from them again because they're made up.
"At United, for the players and supporters, it's all about the next game. Man United, over the past 20-25 years ... we never relaxed. We never thought we were done. It was let's win the next game, the next trophy.
"That's why I think the manager has been so successful. ... He's constantly looking at the bigger picture."
Ferguson's continued success has come under threat this season from United's big-spending local rivals Manchester City, including a humiliating 6-1 home defeat this month.
But Wilkinson believes Fergie will bounce back from what he called his worst moment in football.
"He'll come back even more determined, if that's possible, than he ever was. For him to come out and say that publicly ... that will have cut him to the quick."
Ferguson's reign will not last forever, and Wilkinson believes United must prepare for a reversal in fortunes when he finally steps down.
"You won't be able to replace him. He is, in my opinion, the greatest manager that's ever been, and to think you can go out and pick someone who'll sit behind his desk and just pick up the reins as if nothing has changed -- that's very difficult," Wilkinson said.
"Whoever follows him will need to be the right person, but more importantly the people at the club will need to be patient, because that person is walking into perhaps the most solid culture in a business that there is anywhere in the world."