Mr O'Halloran first uploaded the video to YouTube three years ago, when it was viewed around 40,000 times. It also featured on a Maori Television show of home videos.
The clip gained a second life in January when it was posted on Facebook and widely shared. By last month it had achieved viral status and, as of yesterday, the 99-second clip of the "Maori cowboy" had been watched 395,000 times on Facebook and shared more than 7500 times.
Now aged nine, Snow is more interested in playing league than basking in internet stardom. He still rides Blue but can now mount the horse by more conventional means.
Renowned Hokianga horse-riding teacher Rob Pink said he first came across the clip three years ago and made contact with Snow's family, inviting them to the Rawene brumby races.
"He's a little star. He's fearless," Mr Pink said.
The video brought back memories of his own childhood.
"When we were kids, that's how we'd get on a horse. If we couldn't get it over to a drum or a fence we'd wait for it to put its head down and jump on."