"He always had strong opinions but didn't demand the spotlight. He was always more focused on a good outcome, and then the next task," his son said.
"He had incredibly loyal staff, and he was well loved."
Mr Guy was father to Greg and Kathy, and had several grandchildren.
The vision and stoicism that saw him become one of Northland's most successful businessmen and a generous benefactor also saw him inducted into the Northern Advocate Business Hall of Fame in 2016.
Mr Guy started a carpentry apprenticeship for his builder father, Ted, in 1944 and went into business on his own account in 1952.
Through the next two decades he built the business to the stage where his company was building houses, schools and commercial buildings throughout Northland and Auckland.
He also developed a Whangarei joinery plant that spread to ship fitting and refurbishing.
In 1981 he opened a branch of his building company in Kaikohe.
The largest commercial construction company in Northland, with work from Te Kao to Auckland including schools, shopping centres, hospitals and factories, apartments and office blocks, at its peak Jack Guy Ltd employed 124 staff.
In the 1980s he turned his focus more to property development, building, in partnerships, retail, office and self-storage spaces in Kerikeri and Whangarei.
Mr Guy joined Whangarei Lions Club in 1961 and was an active member for several decades.
In 1974 he rose to New Zealand's top position, chairman of the council of governors.
A huge supporter of local ambulance services, he was a life member of the Order of St John.
In 1986 he was elected in his first of three terms on the Northland Regional Council and in 1989 was appointed to the Board of Northland Port Corporation, including time as chairman in his 10 years on the board.
Jack Guy was known for his quiet generosity when it came to helping someone in a tight spot, for which he has been held in high regard by many.
He believed in putting money he made in Northland back into the region, and supported several local charities, the extent to which will probably never be known.
In 1970 he bought an ambulance and gave it to the Whangarei St John branch.
Thirty years ago he founded the Jack Guy Charitable Trust, offering university scholarships to many Northland students.
The trust, which still makes annual grants to local causes, bought land at Ruakaka and relocated former oil refinery buildings to the site to build the Church of the Holy Family.
Jack Guy was a founding trustee and benefactor of the Catholic Homes Trust which built the Marian Heights Village in Maunu.
The trust also provides emergency housing and will continue to serve Northland long after its founder's death.
His legacy reflects a devout religious side as well as a deep empathy for people, and his love of Northland.
