Mr Pledger attributes his longevity to regular exercise and not smoking - although he admits to smoking fuchsia bark and tea leaves as an 8- or 9-year-old, when "Mum was in town".
His father was a gardener at Ashburn Hall, Halfway Bush, and Mr Pledger attended Wakari primary school, where he was "champion of getting the strap".
"I'd be out rabbiting [on Flagstaff] in the morning and setting the traps at night, so I never learnt my spelling."
Flagstaff has played a part in several birthdays since then, with Mr Pledger walking up the hill - admittedly not from the bottom - half a dozen times on birthdays between the ages of 80 and 92.
He has packed plenty of living into his 100 years.
While working as a ploughman near Clinton, Mr Pledger heard a professional running race was coming to Gore.
"I said I'm going to enter that, so I asked for a couple of weeks off. I'd already beaten the New Zealand champion in a three-quarter mile race at Hampden.
"The prize for winning the race in Gore was 6 and a cup. There was a hell of a wind that day, blowing from Invercargill.
"The other runners were all a lot taller than me and I shot through to win it."
One of his running mates was Jack Lovelock, who won the 1500m final at the Berlin Olympics in world-record time.
After running professionally for six years, earning enough for a deposit on a house, Mr Pledger went to work as an attendant at Seacliff Hospital.
One of his jobs there was to keep an eye on Lionel Terry, an English migrant who was committed after killing an elderly Chinese man in Wellington, an action he justified on the grounds of racial purity.
One of Mr Pledger's other jobs at Seacliff was to look after people with Tb.
"But I caught it myself."
As a result, he ended up with a caliper on his right leg and was on crutches for six years, before medicine became available to treat the condition.
However, it did not stop him building a house for his family in Waitati.
He is the only Pledger to reach his 100th birthday, although his father lived to 90.
He has outlived three older brothers and one younger brother, along with his younger sister.
Today, Mr Pledger will have dinner in the middle of the day at Ripponburn Home, Cromwell, where he has lived for the past three years, before going to his son Colin Pledger's place at Bendigo for an afternoon family gathering.
There he will catch up with between 40 and 45 children, grandchildren and great grandchildren, and wives and partners of those people.
But first he will begin the day as he always does - with a morning walk.
