The 42-year-old recalled how his father had spent “every spare minute” with him as a child, before describing how the former talent agent built his public relations business.
“He built a business with my mum that set the standard for public relations and personality management,” Ben wrote.
Ben went on to say that John had been very charitable and a wonderful donor to various organisations, including the Head and Neck Cancer Foundation, which he established.
“As a mate, he was the best. If any of his family or friends or clients were in trouble, he’d go to war… ’If you grab the tail, you get the whole tiger’ - that was Jack,” Ben added.
“We’re going to miss him but thankfully we took every chance to tell him how much we love him. That’s the trick. No regrets.”
Following the news of John’s passing, many of Ben’s celebrity friends took to Instagram to pass on their condolences to the Fordham family.
Former Today show co-host Lisa Wilkinson wrote: “He left his mark in so many ways Ben. So many achievements, so many passions...but it was you, Sarah and Nick, Maisie and Coco, Freddy, Pearl and Goldie that were his greatest achievements. Rest easy John. All my love Ben.”
Tom Steinfort also passed on his regards, writing: "Thinking of you and the family Fordo."
Current Today co-host Deborah Knight added: "Love to you and your family Ben."
Ben concluded his heartfelt post by announcing that John has also been appointed a Member of the Order of Australia for his commitment to charity.
"RIP John Fordham (AM)," he wrote.