Williams said his time spent in the first XV, cricket and athletics at MAGS is what set him up for a successful sporting career.
This was despite getting caned a few times for "sky larking and talking out of turn".
Making the All Blacks was a dream come true for the teen. He was thrown straight into the deep end with his first tour to South Africa during apartheid. Williams, who is of Samoan descent, explained he was granted honorary 'white status' by the South African government so he could play.
"The tour went really well for me. But it took some getting used to the separation of the races."
Williams' was an All Black from 1970 to 1978 where he played 113 matches and scored 66 tries, a record until it was beaten by John Kirwan.
The 66 year old trained four nights a week when he was in the first XV. He said they'd sprint up steep banks carrying each other or tackle bags because they didn't have weights. After training Williams had an exhausting cycle back to his aunt's house in Avondale where he was living.
"It was in the cold winter and it was dark, I didn't have lights. It's raining and you're exhausted. You soon learn about hard times.
"It wasn't much fun, it was very very hard."
He believed his athletic background, speed and well-muscled body helped him go further than some of his other teammates.
"Then it came to determination and desire. I was willing to train hard everyday to achieve my goals."
Williams said he always aimed to have a balanced life, his star sign is Libra, or "the scales" after all. The former lawyer ensured there was time for family, volunteering and academic work.
"Volunteering gives good balance. It's not just a matter of take, take, take. It's rewarding when you give your time to help your brothers.
"You just have to make sure you're devoting enough time to the things that are important."
Now his biggest job is babysitting his 13 grandchildren, although he is also a patron of the New Zealand barbarian club, on the committee of his beloved Ponsonby Rugby Club and a trustee for the NZ Rugby Foundation.
MAGS headmaster Patrick Drumm said naming the field after Williams was part of a larger project where they were naming parts of the school after significant students or teachers for the school's 100th birthday in 2022.
Williams was chosen out of the 13 other ex-MAGS All Blacks as he exemplified giving back to the community as well as his athleticism.
"He was one of the great All Blacks and one of the great Albertians," Drumm said.
"He models the well-rounded attitude... He's the sort of guy who has always got time for the community."
Among those present to see the special occasion was former All Black coach Sir Graham Henry.
He described the rugby legend as "an outstanding footballer, the Jonah Lomu of the 70s if you like".
He had also said Williams had contributed to rugby massively off the field, including as a coach and administrator.
"He's done everything in the game," he said.
"Apart from being a colossus as a player he has been a colossus as a rugby adminstrator and personally involved in the game. He's a 15 out of 10."
