On the pitch, his skills are sublime. But it seems most, if not all, of Mr Rooney's brains are in his feet. At away matches, the chant is ... well, it's not for repeating here.
So it's no surprise that Coca-Cola dropped Rooney from the Coke Zero team this month.
His boorish behaviour is hardly the qualification for a tie to a mainstream family brand.
As every marketer knows, brand ambassadors can be a risk. Perhaps Coke was a little naive to imagine a kid with Rooney's bad-boy track record was going to emerge any differently.
Humans - just like brand personalities - rarely change fundamentally. Matching the two is one of marketing's dark arts. Who would question the wisdom, for example, of pairing Kevin Spacey's smooth charms with the American Airlines brand?
So, Mr Rooney has been relegated to marketing's subs bench - but for how long? PepsiCo is apparently considering an approach (page 4), but I wouldn't bet on it. Last year, the FMCG giant axed Tiger Woods from its Gatorade adverts after revelations about the 14-times major winner's private life.
Paddy Power, with its history of courting controversy, looks a more likely proposition. While the bookmaker is no longer a market-changing newcomer, adopting the Red Devils' naughty son fits with the brand's edgy persona.
No doubt Rooney's advisers will want another global brand for their talented, but badly behaved, charge, banking on him as an antidote to saintly David Beckham.
With each new unsavoury Rooney revelation, though, which serious corporate can afford to take a risk on him?