He was told it couldn't be done.
Now his team is the most successful in the southern hemisphere, with a potential Olympic superstar in its ranks as 23-year-old Don Opeloge knocks on the door of an Olympic gold medal.
ABC Pacific reports at July's Commonwealth Games, where Samoa cleaned up with five weightlifting medals, the Pacific Islanders reminded Australia and New Zealand they're still the best and they did it again when they smashed six Oceania records at the New Zealand Championships last month.
Opeloge brought home Samoa's only gold medal from Birmingham when he won the 96kg category and kept the good form going when he set three new records in New Zealand.
Commonwealth silver medallist Feagaiga Stowers, the other Olympic hope in Wallwork's stable, also set a new Oceania record, as did two juniors, Tovio Ah Chong and John Tafi.
Opeloge's little sister Avatu Opeloge won her 76kg category alongside teenage teammates Imosina Pelenato and Lesila Fiapule, who also placed first.
A big part of their secret is training locally,
"It's something I've believed in ever since I became involved in sport," Wallwork said.
"Twenty years ago I said I'm going to train a team locally and produce results from a Samoan-based team. I was told it couldn't be done. Now it's been proven."
In the Pacific it is rare for internationally competitive athletes to live and train in their home country on a permanent basis, let alone an entire national squad.
"It gives us the unity throughout the years, you're all part of one team when the whole group is together," Wallwork said.
"Having unity is most important, everything comes after that."
Wallwork, who manages a whitegoods store in Apia, turned to coaching once he retired from weightlifting.
His father, Paul Wallwork, is one of the founders of weightlifting in the Pacific Islands.
He's also the first Commonwealth Games medallist for Samoa and won silver for weightlifting at the 1974 Games in Christchurch.
Wallwork Sr broke his neck playing rugby at the age of 16 and was told he'd never walk again. He started lifting weights to regain strength and went on to become a champion lifter while training in a tin shed in his local village.
His son's Samoa-first approach to the national team is inspired by the achievements of the past.
"We make up for what we are short of here by having all the athletes together in a family atmosphere," Wallwork said.
"It creates that bond and trust between all of us. We all know this is our family here and we must defend it, we must fight for it, we must perform."
The Opeloge family is sporting royalty in Samoa
The weightlifting community believes Wallwork's star lifter Opeloge would've won gold at the 2021 Tokyo Olympics.
But the Samoan government prevented athletes from leaving the country because of a COVID border lockdown.
Wallwork still burrs at the mention of it. Samoa has never won an Olympic gold medal.
Opeloge outclassed his competitors at the Commonwealth Games earlier this year, winning on a 171kg snatch and 210kg clean and jerk.
He was 35 points ahead of the silver medallist, a monstrous lead for the sport.
But Wallwork didn't immediately see the potential in his wunderkind,
"When young Don first came into my gym he was a skinny little kid, and I didn't think he had the talent of his older aunties and uncles."
Those aunties and uncles started the Opeloge weightlifting dynasty.
Niusila first won a Commonwealth bronze 20 years ago.
Then he and sister Ele made history by both winning gold at the 2010 Commonwealth Games.
Their other siblings Mary, Petunu and Tova Opeloge are all legends in Oceania weightlifting.
Ele is the first Samoan to win an Olympic medal in any sport, although she was robbed of some glory.
She was awarded a silver medal two years after the Beijing Olympics because the frontrunners tested positive for banned substances after a re-analysis of samples.
Currently Opeloge's younger siblings Jack and Avatu also represent Samoa in weightlifting.
Wallwork has coached all the Opeloges and said there was more to come with many young cousins coming up the ranks now.
Effort geared towards Paris 2024 Olympics
The Chinese national weightlifting team has dominated for the past few Olympic Games.
Wallwork will take his squad to work with the Chinese at a four-week training camp next year.
"They are the best in the world. So, we will train with the best," Wallwork said.
Next year's Pacific Games and World Weightlifting Championships will be just a pit stop on the road to Paris 2024.
All indicators point to it being a matter of when, not if one of Wallwork's lifters win an Olympic gold medal.
But Wallwork believes his greatest legacy will be proving to the world you don't need to leave Samoa to make champions.
"Training athletes locally if given the right methods and opportunities will exceed expectations and I have shown that now," Wallwork said.