Against France in Paris on Saturday, the 34-year-old is set to join an elite club of men with a century of caps, but more than his longevity in the sport, it is his rags-to-riches story and uniting of South Africans that have inspired his compatriots.
Kolisi has captained the Springboks to two World Cup titles after being appointed the first Black skipper of a team that during apartheid was the exclusive preserve of whites.
His appointment completed the rehabilitation of the Springboks and turned the team into a national treasure when at one stage most of the population derided the emblem.
“Rugby was firmly associated with white national pride, and now a Black man from a humble background has become a national hero, reshaping the sport’s image,” wrote psychology lecturer Tinashe Harry in news outlet The Conversation.
“Kolisi’s appointment as captain in 2018 signalled a new chapter of inclusivity, diversity, and unity.”
Kolisi was brought up in tough surroundings in Zwide township in Gqeberha (formerly Port Elizabeth) by his grandmother after his mother died. He won a rugby scholarship to the city’s most prominent school even though he could hardly speak English.
From there, he blossomed, grabbing every opportunity as he worked his way through South Africa’s testing provincial rugby set-up to earn a first cap in eye-catching fashion 12 years ago.
Kolisi came on as an injury replacement in the fifth minute and went on to claim Man of the Match against Scotland in Nelspruit.
Six years later, maverick coach Rassie Erasmus picked Kolisi to be captain.
“He was always a speedy flanker with grit and toughness,” the Bok coach said in a recent interview.
“But it was his humility and hunger to learn that stood out. A good leader empowers those around him, including his coaches. Siya never expected special treatment; he took every opportunity, worked hard, and never lost anyone’s trust.”
A larger-than-life personality - social media has dubbed him the "Minister of Enjoyment" - Kolisi is well aware how his story offers others a glimpse of a pathway out of poverty.
“Every day I have to carry myself in a way that reminds me that I must push every single time because others are also looking — and hopefully I can be that little bit of hope for them,” he said on the Mind Set Win podcast.
Injury has hampered him of late and his age means his career is coming to a close, although Erasmus thinks Kolisi could still compete at the next World Cup in 2027.
But Kolisi will not lack for opportunity when he hangs up his boots and already has a foundation working on social issues and development programmes from gender violence to feeding the poor.
“When I stop playing, I want to make the world a better place,” he said.