As a player he took no prisoners, as a manager and pundit he doesn't suffer fools gladly.
But Roy Keane has surprised fans after joining social media site Instagram - announcing his arrival with a selfie.
The Irishman is noted for his stern views as a key part of the Sky Sports punditry corps, usually offset by a grinning Micah Richards or Graeme Souness.
And the picture-based platform is about the last place you'd expect him to turn up - but there he is with a blue verified tick to boot in order to weed out the impersonators.
The former Celtic and Manchester United enforcer has just one picture on his profile so far, and is still yet to follow anyone else.
But that hasn't stopped him from gaining hundreds of thousands of followers in a matter of hours.
And it's still heartening to see even one of the hardest men in football embracing Instagram.
It comes a week after he was left disgusted by a viral video of his likeness from the FIFA video game.
Co-pundit Richards showed Keane a video of his digital self busting out some celebratory moves in the popular football title - and had to dub his own audio over the clip to mute the X-rated reaction.
Souness was even left giggling at the hilarious clip from Sky's Super Sunday coverage.
