As a boy, his father died and his mother, although with little money and raising her only son in a council house, had a "passionate belief in the power of education".
"I am grateful now for her belief in education," said the multi-millionaire former politician and investment banker.
"I would never have had the honour and privilege or becoming prime minister of New Zealand or having a career in the markets if I hadn't gone here and earned a degree like all of you have done."
Sir John congratulated the graduates and reminded them that, although everyone experiences challenges, it's their own determination, effort and attitude that will be the biggest determinants in them achieving their life goals.
"Mum told me at a young age, you get out of life what you put into it," he said.
UC Chancellor Dr John Wood described Sir John as "a valued alumnus".
"Sir John provided strong support to the University of Canterbury, especially in the years since the 2010/2011 earthquakes," Wood said.
"His leadership has been critical to the rebuild, not just on campus but in the region in general, and we will be eternally grateful to him for that.
"He has also been a supporter of the university in a personal capacity and I sincerely hope that his connection with this institution will continue and strengthen in time to come."
The past seven-year period has been one of most challenging and difficult chapters in the institution's 134-year history, Wood said.
After the devastating 2010 and 2011 earthquake sequence, the university vowed to stay open, recover student numbers as soon as possible, and take maximum advantage of the "unique opportunity" to upgrade the campus.
Now as the $1.1 billion-plus rebuild programme draws to an end, Wood said the university will now offer some of most modern facilities in the Southern Hemisphere, if not the world.
He said the university was well-positioned to take full advantage of its regeneration, and change its focus from bricks and mortar to "what really counts in university institution, the students and the staff who guide and support them".
About 1300 students graduated from the University of Canterbury this week.