New Zealand's economic cornerstone dairy industry had a lot to thank him for, he said.
Wilson was "the godfather" of the milk price today - it was largely due to his hard-headed insistence on a policy of pricing transparency that dairy farmers receive 40c/kg milksolids more than they did before Wilson entered industry governance in 2003. It was largely due to him that farmers have achieved milk price parity with their global rivals.
"The milk price is all dairy farmers really worry about – we should light a candle to John every season," said van der Heyden who rejected the popular industry notion that Wilson was his "pupil".
"John was always his own man. He knew the cooperative (Fonterra) inside out – often to Theo's frustration."
Chief executive Theo Spierings left Fonterra last year, shortly before Wilson announced he was stepping down as chairman because of illness.
Van der Heyden also credited Wilson for his "relentless" pursuit of capital structure and governance and representation reform for Fonterra and his unflagging championship of the cooperative's farmers.
After world milk prices slumped in 2015 it was Wilson who got the Fonterra board to agree to taking $400 million from the balance sheet to offer interest-free loans to struggling farmers, he said.
"That loan underlines how far he would take that commitment to farmers – no-one else would have been able to do that but John."
There was no skirting around Wilson's propensity to blow his top.
"John had a short fuse to match his red hair," said van der Heyden.
"He loved a good stoush and he was good at it. It's true he had an explosive nature but it had its uses and no-one was harmed."
Noting Wilson's sharp intellect, van der Heyden seemed unaware of the irony of his statement that Wilson "never stopped probing and asking questions". "He was like a dog with a bone."
More than a few of those attending would have asked themselves where was that probing mind when the Fonterra board did due diligence on the $790 million disastrous buy-into China's Beingmate company.
Nor did van der Heyden's use of a eulogy to give the media a serve for hurtful "negative press" about the strained financial predicament of New Zealand's biggest company sit comfortably with the occasion.
Close friend of 25 years, Tatua Dairy Cooperative chairman Stephen Allen noted Wilson's "incredible mind with a sharpness that could sit you on your backside in an instant".
Allen saluted Wilson's huge work ethic and tireless pursuit of security for future generations of Wilsons and his beloved dairy farming businesses in the Waikato and Canterbury.
"Some say he had a hide like a rhino. Well he needed it."
Allen said Wilson was a champion for New Zealand champion who lived his life behind "an iron-clad shield of privacy" – particularly about his beloved family over which he "was really as soft as butter".
And it was the eulogy from Wilson's wife Belinda and four daughters that perhaps said most about the character of a man whose death came as a shock to many.
Individually they faced the huge crowd with courage and composure.
Daughter Sophie said her father "raised us to be brave and strong – he would have expected us to be up here".
Her sister Tessa recalled Wilson's huge passion for skiing which "gave us our competitive spirit – we will never give up" while Libby saluted her father for sharing his love of farming.
Daughter Victoria – according to Allen, "the only person who frightened you John" – said Wilson taught his family "never to falter".
"You created a legacy to live by."
