Mr Williams, who has had a connection with the area since he was a teenager, applied for the job in 2003 after a neighbour told him about the vacancy. The event had just $34,000 in the bank and police had previously been dealing with fights that nearly became riots and numerous cases of hypothermia.
Today, there's a quarter of a million dollars in the kitty - funds that go back to the community through a trust - and police haven't arrested anyone within the venue for years.
Of around 6800 people who packed the event last year, 20 were arrested outside the venue, most of them for breaching the liquor ban, and just two for disorderly behaviour and fighting.
For Mr Williams, a successful event hinged on a healthy turnover - the event generated $1.2 million for Ohakune last year - and equally importantly, people having a good time and nobody getting hurt.
"We are dealing with young people coming to a have a drink and to have a party, and you are always seeing the reality of this country's obsession with alcohol. But we are pretty robust in dealing with those sorts of things."
Planning has sharpened to the point where police begin their own preparations in January, and the alcohol management plan that Mr Williams developed with St John, police and the local council is now used as a template elsewhere.
When locals were surveyed over their support for the event four years ago, the response was overwhelmingly positive, he said.
"There's none of that aggro anymore, and we haven't had a major incident for six or seven years. We have brought it a long way."
And Mr Williams, essentially a one-man-band who has also piloted the 2011 Rugby World Cup fan trail and the Auckland Lantern Festival, has become so deft at his job that last year he organised it by laptop in Italy.
"But at the same time, you can never be complacent - the moment you think you know it all is when something sharp and nasty comes and kicks you up the backside," he said.
"I spend the last week double checking and triple checking events. There's a lot of ringing people up and texting artists."
Late last year he decided that he'd like to spend more time with his children and take a back seat in running the festival within three years, and be out of the game altogether by 2017.
"There comes a time. I'm 53, and you've got to find new challenges," he said.
But before then he'd like to see the event's proceeds offer more opportunities to locals - especially young Maori - and for someone in the community to step forward.
"If I was able to walk away from it and know that's where it has gone, I'd be delighted."
Figures
• 6,800 - Revellers at last year's festival
• $1.2m - Value to the local community
• 14 - Drink drivers caught last year. Police will be out in force again this weekend.
Who's playing: P-Money, Dick Johnson, Tiki Taane, Banglade$h, PleasePlease, DJ Lyrakill, DJ Mikael Wills. 7pm tonight at The Junction, Thames St, Ohakune.
