"I was lucky in that my dad was a professional rugby player in his generation so sport was always, you know, bred into me as a youngster."
Perhaps of equal significance to junior was that his father was a schoolteacher who was partial to just about any sport at school.
Having a cricket net at home proved to be a catalyst in honing his skills after school and on weekends.
"I would hit some balls and it was always a case of him saying, 'Okay, that's enough now, you've done too much'," the Pretoria University graduate says.
Indubitably cricket started eclipsing rugby.
"I then got really serious with it [cricket]."
That gravitational pull meant du Plessis consciously singled out Afrikaanse Hoer Seunskool (Afrikaans High School for Boys, commonly known as Affies) and not long after he forged cricketing ties with a fellow pupil who is now his captain, AB de Villiers.
"We were in the same years there and we had a nice cricket team. We were No1 in the country," du Plessis says of the Pretoria high school, hailing it as one of the two best boys' sporting schools in South Africa.
"We used to play for three-quarters of the year and played against the best in Johannesburg," says the man who progressed through myriad age-group provincial teams before breaking into the national under-19s.
"When I came out of school there were very good international players so you had to fight your way into a team and that set you up for doing well and fighting your way into the national side."
A rugby centre, du Plessis again found himself next to de Villiers in the school's 1st XV.
With cricket blossoming, du Plessis had decided to take a break from rugby but the lure of "playing one more game for fun and giggles" taught him a lesson in the game of life.
"So I said I'll come back and I broke my wrist," he says with a wry smile, revealing the agony of missing four weeks of cricket.
"It was just a bad decision to go back for that one more game.
"I love rugby but cricket is my favourite game so rugby took a back seat for me from a very young age."
The right-hander, who bowls right-arm leg breaks, heaps plaudits on his international skipper and world-class batsman, de Villiers.
"He's a great human being, first of all.
"His standards on life and morals are very good.
"I've always looked up to him as a person but [with] cricket we know each other very well, on and off the field," he says of a man he has known since the age of 13.
"I understand what he does well and what he struggles with.
"Luckily now, he doesn't struggle with too many things when it comes to batting," he says, adding they possess a good rapport on the batting crease.
Du Plessis has reportedly featured in a music video of a duet between fellow players de Villiers and Ampie du Preez.
He harbours the desire to shuffle up to No4 in the batting line up with the Proteas.
"That's where I've been batting in my first-class and domestic career and that's where I've done my best.
"I like coming in having lots of time ... but that's how it works in international cricket where you have to start at a certain place and work your way down."
For the record, de Villiers scored an unbeaten 106 last Saturday at No 4 in the Proteas' six-wicket victory against New Zealand in Wellington.
Du Plessis was 66 not out at No5 although Jean-Paul (JP) Duminy has expressed a desire to play in the No4 position as well while enjoying No5.
"I'm enjoying the position [No5] but I obviously prefer to bat at No4.
"I've been batting at No5 for most of my international batting career but I'm grateful for the opportunity.
"If the opportunity arises for a move in the future I'll grab it with both hands," the diminutive Duminy has revealed.
With a plethora of top-order skills, du Plessis hopes in a couple of years he will find his preferred perch in the Gary Kirsten-coached team.
Du Plessis has left an indelible impression on Lancashire in County cricket in England since making his debut in 2008-09, not only as an allrounder but a "brilliant fielder".
He became surplus to requirements in 2010 due to England's immigration policy pertaining to County cricket.
"When I look at my batting I always want to have a good intensity and the running between the wickets as well," says the player who won a US$120,000 contract with 2010 champions Chennai Super Kings in the IPL auction last summer.
"I think if you can pick up the singles and twos on a regular occasion then you're under a little less pressure.
"When you do get used to the wicket and the bowlers then you start looking for the boundaries."
Expecting a slow and low English-type wicket in New Zealand, du Plessis is pleasantly surprised to find "nice and quick strips with a fair bit of bounce".
In keeping with the pre-match ritual, he talks up the Black Caps' nous.
"You can't give them a sniff. We are aware of that and know we have to play well to beat them."
He reflects the tourists' mood in not just wanting to clinch the second ODI today but a 3-0 whitewash before the test series next week.
Claiming the bragging rights to No1 in the world isn't far from their minds.
"I won't say it's bothering us too much. We're just worrying about our performances and the rest will take care of itself.
"It's not something we talk about but it's there."
Whether it's a task of going in to rebuild an innings or "smoke it [the ball] out of the park", du Plessis believes he's got the necessary credentials to deliver.
"I understand different situations so we'll see what comes up in the game."
New Zealand (from): Brendon McCullum (c), Martin Guptill, Rob Nicol, Kane Williamson, Jesse Ryder, James Franklin, Nathan McCullum, Andrew Ellis, Tarun Nethula, Kyle Mills, Tim Southee, Andy McKay.
South Africa (from): AB de Villiers (c), Graeme Smith, Hashim Amla, Jacques Kallis, JP Duminy, Faf du Plessis, Justin Ontong, Albie Morkel, Johan Botha, Robin Peterson, Wayne Parnell, Dale Steyn, Lonwabo Tsotsobe, Marchant de Lange, Morne Morkel.