The powerful 25-year-old centre-back was born in France and represented the country of his birth at under-20 level, but he accepted the call from coach Aliou Cisse in September 2015 to help the Lions of Teranga qualify for the Africa Cup of Nations.
"Senegal have a magnificent team. There are young players, a lot of whom have played in France and now in England."
Having waited for the call that never came, Koulibaly was astounded to hear France coach Didier Deschamps cite his name in an interview on French television last year when asked about players who he was monitoring.
"I was watching the programme without really paying attention and then I heard my name. He must have missed something. I don't blame him for it," said Koulibaly, who is now focused fully on helping the country of his roots.
Runners-up in 2002, Senegal have never won the Africa Cup of Nations before.
However, the presence of players such as Idrissa Gueye, Cheikhou Kouyate, Sadio Mane, Moussa Sow and Koulibaly in their squad means they are one of the favourites going into this year's tournament in Gabon.
In a Group B also containing much-fancied Algeria, Tunisia and Zimbabwe, Senegal should at least make the knockout rounds, something they failed to do in Equatorial Guinea two years ago.
"Our common objective is to get past the first round," admitted Koulibaly, who has shaken off an injury to make the squad, after an audience with President Macky Sall.
Finishing ahead of Algeria would be no mean feat, and the sides will meet each other in a likely group decider in Franceville on January 23.
Algeria have a star-studded front line, but none of them will relish coming up against Koulibaly, a player revered at Napoli and described by club legend Diego Maradona as a "phenomenon".
After modest beginnings at Metz, the defender starred for Genk in Belgium, earning himself a move to Napoli in 2014 when Rafa Benitez was still in charge of the Italians.
Koulibaly did not initially believe the Spaniard could possibly be interested in him, saying: "I thought it was a friend joking around."
But the move happened and the player's stock has risen to such an extent that English Premier League leaders Chelsea have been linked with a mega bid of £50 million ($60 million) for his services.
Nevertheless, his presence in Gabon allied with Napoli's continuing involvement in the UEFA Champions League means any transfer will surely have to wait until the end of the season at least.