In late 2019 O’Sullivan felt an unusual vibration through the right side of his body after using a hand dryer.
Similar sensations began to return whenever he used electrical appliances.
It wasn’t until mid-2020 that he saw a neurologist. In December that year, after scans and biopsies, he received the diagnosis: a brain tumour.
Identified as glioblastoma, the most common and aggressive primary brain tumour in adults, it’s a type of cancer that grows and spreads fast.
Surgical removal was too risky.
“There was an initial shock,” he said of his fate.
“But after that, as I’m a very much a realist person, … I just accepted … and decided to focus on the positive things.”
He sees himself as “lucky” and says family support, and his philanthropic work play important roles in how he faces each day.
After undergoing radiation and chemotherapy, he started the immunotherapy treatment.
“It teaches your good cells to fight the bad cells, the cancer cells,” O’Sullivan says.
One of the only noticeable effects of the tumour is a mild speech aphasia, which slows his speech, prompting him to always carry a notebook to stay on track.
But it hasn’t slowed his spirit.
Born in Dannevirke, O’Sullivan said he learned to work under the principle of “sink or swim”.
And he swam.
He spent decades working in business and still is the force behind the awarded family-owned Tumu Group, which employs over 600 people across the East Coast.
But he says his greatest achievement is giving back.
Since founding the Evergreen Foundation in 2014, the charitable arm of Tumu Group, he has been supporting causes from youth mental health to rehabilitating prisoners through employment.
O’Sullivan has invested significantly in local infrastructure and organisations including the Hawke’s Bay Community Fitness Trust, Hawke’s Bay Rugby Union, Hawke’s Bay Rescue Helicopter, the Hawke’s Bay Foundation, Te Mata Peak Trust and Kaweka Hospital.
“The philanthropic work is part of the positive spiral,” he says.
During Cyclone Gabrielle, O’Sullivan helped raise more than $3.6 million through the foundation for recovery efforts across Hawke’s Bay, especially in the horticultural and agricultural sectors.

That has just been documented in a new book, People Helping People, which shares the stories of generosity, action, and community partnerships behind the fund.
“The Evergreen Cyclone Relief story is one of generosity, action and partnership. Evergreen Foundation has been a vehicle, a facilitator, and a connector,” O’Sullivan says.
“The heroes of the story though, are our donors and all the people and volunteers who have helped our region to recover and our people to heal.”
O’Sullivan was named an Officer of the New Zealand Order of Merit in this year’s King’s Birthday Honours — one of the highest honours available — for his contributions to business and philanthropy.
Throughout his life, he took on leadership roles across many New Zealand companies, only recently stepping back because of his diagnosis.
“A good manager should be looking to make themselves redundant,” he says.
Nowadays, O’Sullivan works three days a week.
“I had very good, capable people around that could quickly step up and take on that responsibility.”
He says the support he gets from his team at the company, including his brothers Brendan and Barry, as well as his wife Michelle, his four children, and even his dog Charlie is what makes him keep going.
“I had a strong will, because I still had people that I wanted to make the most of the journey with.”

O’Sullivan says he wants to be remembered as “a good person”.
His wife, Michelle, says he is much more than that.
“We all want to be like John,” she says.
“He has strong values and empathy for others … and he really makes the most out of every day. Even if it’s a Monday, and it’s lunchtime, every day is a special day. He doesn’t take things for granted. He gives his 100% all the time.”

With tears in her eyes, Michelle added.
“Even on the harder days, he always chooses to find the positive. That’s who he is, and that’s why he is our rock.”