The coach's future had been subject to speculation throughout the tournament, and he has now revealed that he gave the Nigerian Football Federation (NFF) his notice shortly after the 1-0 final win over Burkina Faso on Sunday.
"I did what I feel is right by resigning," Keshi told Metro FM. "I gave the NFF a letter last night [Sunday] after the celebrations."
The 51-year-old Keshi made 51 appearances for the Super Eagles as a player, and he has held coaching posts with the Togolese and Malian national teams. With Keshi stepping down, someone else will be charged with leading Nigeria at this summer's FIFA Confederations Cup, a tournament for which Nigeria qualified by virtue of winning the Cup of Nations.