Kohli has taken over from the great Sachin Tendulkar in the number four position in the Indian batting order and with those massive shoes to fill, showed touches of genius, and no shortage of courage, in his 181-ball innings that included 18 fours.
"I was not thinking about pitch conditions, the movement and bounce. I had a game-plan that I wanted to stick too and I did that. Getting to 100 was an amazing feeling, very satisfying," Kohli told reporters.
"You have to respect the good balls, but at the same time you have to cash in on the bad balls. And I did that."
Kohli put on 89 with Cheteshwar Pujara (25) for the third wicket and 68 with Ajinkya Rahane (30 not out) for the fifth as India patiently played their way out of early trouble having won the toss and elected to bat.
When Kohli's demise came, it was surprisingly soft. Jacques Kallis floated a half-volley outside off-stump and the centurion guided it straight to JP Duminy at cover.
Kohli stayed motionless for some time after the shot, perhaps disbelieving of his generosity just when he had seemed destined to kick-on for a big hundred having surpassed his previous test best of 116.
MS Dhoni (10 not out), captaining India for a record 50th time, will resume on the second morning with Rahane at a ground where India have never lost a Test in three previous matches.
"Hopefully we can build on this tomorrow in the first session, overall I think we can be pleased with the way the first day went...we could have been a wicket less maybe," said Kohli.
"We would love to have 400 on the board. If not, anything above 360 or 370 would mean South Africa need to score 500 to put us back under pressure in the game."
South Africa bowled well in patches, especially the morning session when they were getting the most assistance from the pitch and were able to exert pressure on the batsman that was released somewhat after lunch.
Morne Morkel impressed with his steepling bounce in his first spell and deserved more than just the wicket of Murali Vijay (six) who was caught behind by AB de Villiers. Dale Steyn beat the bat with regularity, his only reward the wicket of Shikhar Dhawan (13), caught by Imran Tahir at fine leg attempting an ill-advised hook.
Pujara was the victim of some poor calling from Kohli, who initially asked for a run having tapped Tahir into the onside and then sent his partner back to the non-striker's end where he was well short of his ground as Hashim Amla removed the bails.
Vernon Philander had Rohit Sharma (14) caught behind to get in on the wickets, as all the South African pace-bowlers played their part in restricting the run-rate.
It was the spinners who eased the pressure on India, Tahir and Duminy going for 77 runs in just 13 overs combined.