As a player he was famously uncompromising and had a reputation for a bluntness that could be staggering. As a manager, Roy Keane's reputation has been transformed. The man who divided a nation over his stance at Saipan seems to have become perhaps the most thoughtful, considered and downright likeable football manager in the game today.
BBC sports anchor John Inverdale is one of the more high-profile figures who has been smitten with Keane's charisma.
"Switch on Match of the Day on a Saturday night, and who's the manager who talks the most intelligently, rationally and without hyperbole?" he asks.
"Who has an authority and a presence that commands and demands your attention? Who has assumed the mantle of a managerial statesman within a very short period of joining that rag-tag band of winners and losers?"
The days of ranting and raging are long gone, but it doesn't mean Keane has turned from red to grey. He still has strong opinions about everything from WAGs to prawn sandwiches, but they're delivered in the measured tones of management, not the shrill shriek of the shop floor.
Ian Laws, football writer of the Sunderland Echo, says any fears over Keane's suitability for the job when he was appointed disappeared within months. "There were a lot of fans who thought he wasn't the right man to lead the club back to the Premiership, but nobody feels that way now.
"He has proved himself to be not only a very astute manager, quite different to the reputation he had as a footballer, but an exceptionally engaging individual who never shirks questions. He's also very funny and engaging -- press conferences with him are never boring."
Laws says the 36-year-old Corkonian has stamped his managerial style all over the Stadium of Light. "In his book, Keane offered his views on what makes a top-class manager, taking Brian Clough [his old boss at Nottingham Forest] as an example," he says. "Keane believes good football management is all about getting a thousand little things right, and there are telling examples of that since he took over.
"The way the players dress and look is important to him. He refuses to let the squad members who aren't playing on the Saturday wear tracksuits to the game," he says. "They have to wear the official club suit. And small things like that can make a difference towards overall mentality within the players."
Laws' views are typical of the reaction of newspaper and radio reporters on Wearside. In the words of one, he's "unrecognisable from the snarling rottweiler of old". Suddenly you can use the words 'charming' and 'Roy Keane' in the same sentence.
Except it's not that sudden. When you then chat to other top Irish sportsmen from disciplines as disparate as rugby and racing, they will tell you past tales of immense generosity, one in particular to an injured rugby player, that sets Keane apart from the crowd. And they will all tell you that when they're instructing or coaching young up-and-coming stars, they offer Keane as the ultimate beacon to whom yuo should aspire. His influence extends into sports far divorced from football.
The captain of the Ireland ladies' hockey team, Nikki Symmons, spoke recently about how the example of Keane's steely determination had helped her in her drive for excellence. "People gave out about Roy Keane for his attitude, but that's the way you have to be. You have to have everything right. You have to try to be the best you can be, otherwise you'll never get there."
When former Cork hurling manager John Allen invited Keane to address his players on the eve of a crucial game two years ago, he was struck by the footballer's low-key approach, generosity with time and ability to inspire.
A figure close to Keane believes he is outwardly a remarkably different animal to the often combustible player. "He's always been a highly charismatic guy, it's just that the rest of the world is getting to see that now. He kept that side of him hidden when he played football.
"In management, however, he's quickly learned that you need to approach things like the media differently.
"He doesn't really go in for the Fergie hairdryer treatment, and the famous Roy Keane temper seems to be put to bed. He seems to be quietly encouraging players rather than intimidating them.
"He wasn't the most media-friendly of characters when he was a player. But as manager, he's become a journalist's dream. People talk about his ability to make you feel good about yourself, which is hardly something you could say about any of his contemporaries."
That charm seems to be felt particularly acutely by women. Inverdale again: "Watching the telly last Saturday, one of my female BBC colleagues didn't want to hear particularly what he was saying about the Chelsea game, but instead just swooned at his eyes."
Kickette, a website devoted to the aesthetic qualities -- or otherwise -- of footballers in the Premiership, recently mused about the sex appeal of England's top flight managers. "The hottest manager now that Jose [Mourinho] has departed us (sadly, for he was amazingly hot)?"
Many of the respondents plumped for the Corkonian, with the following posting typical: "Most definitely Roy Keane. Hot, not that old, dresses smartly (in his suit), has a great sense of humour, was a great player and shaping up thus far to be a pretty decent manager. He's not quite as arrogant or nonchalant, but he's most definitely hot."
Of course, Keane's charms haven't won everyone over. His ghostwriter Eamon Dunphy has gone on the offensive in recent weeks, claiming Keane's new-found accessibility and willingness to field any question has diminished him.
"This is a sharp, smart, outstanding human being and he's just been sucked into that awful Premier League vacuousness," said the controversial RTE pundit. "It's sad to see Roy Keane bulls******g, but he is."
And Keane's old bite hasn't entirely gone away, you know. Out-of-favour Sunderland player Liam Miller will attest to that. Fed up at Miller's persistent lateness, Keane promptly slapped him on the transfer list.
"He is a Cork man, like me, and I have looked out for him on a number of occasions," according to Keane. "But there's no room for sentiment. I have been more than fair."
But this being Keane, there was room for the humour that's quickly becoming a new trademark. "If you are driving to work, don't get in the car with Liam Miller because he has more car crashes than anyone I know."