But one Kiwi scribe has blasted the seemingly generous act as a betrayal of his teammates and New Zealand fans.
Writing in the New Zealand Herald, columnist John Roughan called SBW’s kindness merely the “latest in a long line of strange behaviours” by the All Blacks’ super sub.
More: SBW gives away RWC medal
If you somehow missed it first time round, Williams and his ABs teammates were taking in a celebratory lap of the field after their 34-17 win over the Wallabies in the RWC decider at Twickenham last weekend, when a young fan jumped onto the pitch before an overzealous security guard tackled him from behind.
Williams helped the kid to his feet, mugged for a few photos and draped his winner’s medal around the young lad’s neck.
Social media exploded and Williams was hailed as a selfless hero.
But Loughran sees it differently.
He reckons the gesture was “a trifle excessive” and “a bit demeaning for the prize the All Blacks had just won.
“I wondered what his teammates thought,” Loughran continued.
“He is not alone among top sportsmen in having little interest in keeping memorabilia – but it is fairly unusual to give it away a moment after it has been draped around their neck. Insulting too.
“His teammates might never say whether they found it insulting but as a fan, I did.
“It felt like a betrayal of our enthusiasm for their achievement and the exquisite agony of those early mornings on the couch.
“I don't know whether I'm more disappointed in Williams or the many who see it as an utterly admirable act of generosity.”
Loughran goes on to suggest the boy would be more deserving of the medal if he was “tragically disabled or had suffered some heart-rending misfortune.”
The Kiwi writer doesn’t really explain what bothered him so much about SBW’s act, other than to say it was insulting to his teammates, and he concluded with this pot-shot at the Chiefs midfielder.
“Next year Sonny Bill is going to play sevens to go to the Olympics. For a medal? It is hard to know why he does what he does, or what he will do next. He pleases himself.”
It was the second stirring moment Williams had given the World Cup in as many games after images emerged of him consoling defeated South African centre Jesse Kriel following the semi-final the week before.
To attack SBW's gesture seems tone-deaf and a bit heartless. Questioning his motives shows a sad cynicism out of sync with moment and out of touch with the tournament as a whole.
If John Roughan is disappointed in everyone who admired SBW's generosity, I guess 95% of the population is just going to have to live with it.
Shouldn't be too hard I don't think.