The softly spoken 25-year-old refers to himself as "ordinary, very boring" and "average."
Listening to him speak, it's easy to forget this is the man tipped to fill the void left by Usain Bolt's impending retirement from track and field.
Already an Olympic champion -- and now a world champion after victory in Tuesday's 400m final -- the South African is the only man in history to have run a sub-10 second 100m, sub-20 200m and sub-44 400m.
And on his way to gold at Rio 2016, Van Niekerk shattered Michael Johnson's 17-year-old 400m world record.
Eight-time Olympic champion Bolt, the fastest man in history, has been glowing in his praise, backing Van Niekerk to "take over" athletics in a recent interview with CNN.
But perhaps he has already. Van Niekerk's impressive times in the 200m this season -- his 19.84 second run in Jamaica last month is the second quickest in the world this year -- were enough to convince Bolt not to race over that distance at the IAAF World Championships in London.
Now, the understated South African has set his sights on the great Jamaican's 200m world record.
"If you had asked me a few years ago if the 400m world record is possible, I probably would have been shocked," Van Niekerk told CNN.
"Now I'm thinking why not, because I never thought I'd be owning the 400m world record today, so why not believe in the 200m?"
Bolt's support giving confidence
Prior the the World Championships, which end on August 13, Bolt said he believed Van Niekerk was "doing a lot for the sport." His support hasn't gone unnoticed.
"I should owe him a fee for the amount of recognition he's giving me," Van Niekerk quipped. "It gives me, obviously, a massive boost in my career.
"But, at the same time, it makes me feel good because he respects me as the person I am and I respect him as the person he is. It gives me great confidence to continue achieving great things.
"I'm getting the backing of a legend of the sport and he believes in the great things I can do and become a legend in the sport."
As Van Niekerk was striding into Olympic history in Rio, Bolt looked on in awe.
Making his way onto the track for the 100m final, the Jamaican's reaction to Van Niekerk's 43.03-second lap became one of the enduring images of the Games.
Mouth wide open, hands clasped over his face, Bolt summed up the feelings of everyone watching in the Olympic Stadium and around the world.
An overnight star
However, Van Niekerk's athletics journey actually began with the high jump, before he transitioned into the 100m and 200m.
Injuries soon forced him to abandon the shorter sprints and take up the longer, more grueling 400m.
He soon discovered a natural talent.
"My time just started growing year in, year out," he recalls. "I started climbing the ranks every year and I started saying: 'Okay, something is happening so let's invest proper time in this journey.'
"Year to year I just went from strength to strength, from South African records to world record and now I think the sky is literally the limit.
"If I think to a few years back to where I was and where I am now, why not dream for even more impossible goals?"
That race in Brazil turned Van Niekerk into a star overnight.
Typically a reserved character, it's something that hasn't always come as naturally as it does to the charismatic Bolt.
"It's so difficult, eh, because I really see myself as such an ordinary, very boring person to be honest," he says with a slight grin.
"I never really saw myself as a public figure, or someone that would be in the spotlight, and now I'm really there. It's something I need to get used to and get comfortable with.
"So, hopefully, in the future, I'll slowly but surely start warming up and show some character. But right now it's extremely difficult for myself."
Van Niekerk has an exhausting six races in six days across the 200m and 400m, as he aims to break two world records and win two gold medals at the World Championships.
The South African is hoping his achievements can inspire others to do great things, but says the thought of leaving a legacy of his own hasn't yet entered his mind.
"I can show an authentic and natural person that really just goes out there and tries to reach their dreams, and show them that any average person can reach whatever dream they want," he says.
"I'm more than happy if there comes a legacy with that.
"Obviously, it's a massive honor but right now that's the last thing we focus on. Right now it's just about becoming the best athlete that I can be."