"I don't know anyone more devoted to the industry to try to make sure everyone benefited."
Wilson's trademark was his strong will and strong opinions.
Penno said this was a result of Wilson "thinking deeply about things" and being prepared to stand by his views.
Waikato dairy farmer and Fonterra shareholder Garry Reymer said Wilson was a "straight shooter".
"He was direct and strong in his opinions. It took a lot to change his mind and discussions were robust. But you still walked away mates. You'd thrash it out and then get on with your lives."
Federated Farmers vice president and dairy farmer Andrew Hoggard recalls Wilson was "passionate and dedicated to Fonterra".
"He was there since day one - he gave nearly 18 years to one organisation, that's a huge level of commitment."
The industry's second biggest exporter after Fonterra is Open Country Dairy. Its chairman Laurie Margrain said: "John gave a lifetime to the dairy industry and we should all be grateful he did".
"We didn't agree on all aspects of the dairy industry's future but we always had great respect for his commitment and contribution to the industry. Our industry needs people of vision and commitment such as John."
Federated Farmers dairy chairman and Waikato farmer Chris Lewis said Wilson was "fiercely" proud of Fonterra.
"He was very upfront and a straight talker. He always had a memory for names. He was a smart, intelligent guy."
Wilson, who was a Nuffield scholar and inaugural chairman of the Fonterra shareholder watchdog, the shareholders' council, announced his intention to step down as Fonterra chairman in July last year to focus on his health.
He left the Fonterra board in November.
His departure came soon after the exit of former chief executive Theo Spierings and during a financially turbulent time for New Zealand's biggest company.
Wilson took over the board leadership in 2012 from former chairman Sir Henry van der Heyden.
During his six years at the top table Fonterra dealt with the false botulism contamination scare which cost it damages and customers, a flood of milk production, severe drought and a milk price slump.
He oversaw major capital spending on processing plant as Fonterra grappled with record milk production and loss-making investments in China.
Fonterra last year announced its first ever net annual loss - of $196 million - and revealed debt of $690m.
Following the departure of Spierings and Wilson, new chairman John Monaghan and interim chief executive Miles Hurrell announced a major internal review of the farmer-cooperative's assets and strategy in a bid to relieve the stretched balance sheet and retain credit ratings.
Monaghan in a statement said Fonterra had lost a friend, colleague, leader and industry champion much too soon.
Wilson is survived by his wife Belinda and four daughters.
