Before him, only backs George Gregan and Adam Ashley-Cooper had managed that feat.
But more than that, the 34-year-old prop is an icon to his younger teammates, particularly those competing with him for a starting berth.
"Slips is a legend of rugby and probably one of the best frontrowers Australia has ever had," said Angus Bell, 22, who will start in Slipper's preferred position of loosehead in Saint Etienne on Sunday.
What makes Slipper stand out is that in an era of ultra-specialised frontrowers, he will line up against Fiji at tighthead, despite being picked as one of the team's three loosehead props in France.
Slipper has moved between the two prop positions throughout his career, with head coach Eddie Jones paying tribute to his "courage and resilience" when picking him to stand in for the injured Taniela Tupou against the flying Fijians.
Slipper will earn his 132nd cap, edging him closer to Gregan's all-time Wallaby record of 139 test appearances.
Gregan himself has said he cannot think of anyone better to beat his mark.
"Hearing words like that from someone like George, it's humbling," Slipper said on Saturday.
"He's a Wallaby iconic player, he's a legend of our game in Australian rugby. A little bit inside of me doesn't want to break his record just for that fact."
Slipper added: "I didn't come over here to break records, I really wanted to come here and win the World Cup."
And he remains a reference for his younger teammates, even when they are competing with him.
Bell made his Wallabies debut as a 40th-minute replacement after Slipper was injured playing against New Zealand in November 2020.
The pair have known each other for a long time.
Bell's father Mark, who won one cap for the Wallabies in 1996, used to coach Slipper at the Reds, before later coaching his own son at the Waratahs.
Slipper even took the young Bell under his wing.
"It was sort of like a mentorship role. Slips is just good because obviously we had connections prior through my father coaching him," said Bell.
"He just reached out after I played my schoolboy stuff ... and he just wanted to mentor me and he did that until I came through to the Waratahs and obviously now I'm lucky enough to get to play with him."
The veteran may not be able to match Tupou's power but he contributes more than just experience.
"He brings a lot of edge and also to our defence, also mauling and the set piece," said Bell.
- 'Huge inspiration' -
With Slipper picked at tighthead, 25-year-old Blake Schoupp kept his place on the bench as Bell's replacement.
Asked about what it means to play with Slipper, Schoupp said: "Massive, not just for me but for every frontrower in Australia, he's a huge inspiration.
"We're just lucky to have him in the squad still and for me personally, growing up he was someone I idolised and to rub shoulders every day and watching him going about his business is good enough for me."
Schoupp has even thought about trying to emulate Slipper by developing the ability to scrummage on both sides of the hooker.
"I've spoken to Slips and Hat (Neal Hatley), our scrum coach, about possibly long term upskilling as a frontrower and it's definitely something I've thought about."
Schoupp remembers as a child watching Slipper on television.
He was 12 when Slipper made his Wallaby debut in 2010.
"I don't want to make him feel any older than he already is, but yeah I have mentioned it a couple of times," quipped Schoupp,
"There are a couple of running jokes about his age but he's still playing some of his best footy and that's what's impressive about him."
Slipper said both looseheads were keeping him on his toes, especially Schoupp, who as recently as the turn of the year was still teaching in a Sydney school for special needs children.
"It's awesome to see both of those players really playing well. Belly's been outstanding for us," said Slipper.
"He's been one of our best forwards, and Schouppy's had a wonderful journey, hasn't he? His story is remarkable."
