Atonio attended Jonah Lomu's old school, Wesley College in south Auckland before playing for Samoa under 20s thanks to parental links after being turned down by the All Blacks' junior side.
In 2011, the 147kg forward signed a contract with La Rochelle in the French second tier aged 21 after being spotted by the club's then coach Patrice Collazo at a tournament in Hong Kong.
Since his arrival on the Atlantic coast, the club has gained promotion to the lucrative Top 14, won the European Champions Cup and become a mainstay in Les Bleus' side, months out from hosting the Rugby World Cup.
"When you watch La Rochelle playing from a distance and you don't know him, he's someone that grabs the eye straight away," the club's current director of rugby Ronan O'Gara told AFP on Wednesday.
"He's open to learning, he has a growth mindset, he wants to get better, his skills are already good.
"I enjoy being in rugby by being around people like him," the former Ireland fly-half added.
Atonio, who started playing at centre or back-row and stands 1.97m tall is seen as a father figure in the La Rochelle and France dressing rooms.
Turning 33 next week he is the oldest member of Les Bleus' squad and only midfielder Gael Fickou has more caps.
"He's brilliant. He’s very generous with his time, looking out for people, team-mates that aren't on top form he'd be the go-to guy," O'Gara said.
"He does an awful lot of selfless work for people in the shade.
"That's very important too because a lot of players can resonate with him, they go to him if there was ever anything they needed.
"That's the mark of esteem he's held by other people," he added.
Aladdin's genie
Atonio, who once played the role of Aladdin's genie while studying performing arts, made his Test debut in 2014.
He has claimed a place in the France team under Fabien Galthie as his ability to last to the 50-minute mark has improved.
"These are the things that make the difference in big games," O'Gara said.
"The trick for Uini to be world class is to keep that fitness there with a run of games.
"He has a god-given talent too. He was made to play rugby," O'Gara added.
Atonio will reach his half century in Paris alongside domestic team-mate Gregory Alldritt after missing two games, wins over Scotland and England, serving a suspension for a high tackle.
"He's a golden person," No. 8 Alldritt told reporters.
"When he's not part of a team, be it La Rochelle or France, you really feel something is missing, be it on or off the field.
"People feel his absence, that says a lot," he added.
