The Dane beat Venus Williams in straight sets -- her first ever victory over the American -- to make amends for the defeat she suffered in her only previous appearance in the final of the year-ending championships.
In 2010, the then world No. 1 Wozniacki lost to Kim Clijsters in three nail-biting sets and, seven years on, the Belgian was on hand to present Wozniacki with her trophy.
"It feels amazing, I can't believe I am here as the winner," the 27-year-old told BT Sport.
"Venus Williams is a great champion and she made it very, very difficult for me. This is my biggest title to date."
Wozniacki had lost all seven of her previous encounters with Williams, winning just one set in a run stretching back an entire decade, but held her nerve in a tight first set to win 6-4.
She then raced into a 5-0 lead in the second set, before Williams won four straight games to get back on serve.
Just when it looked as though the momentum was with Williams and Wozniacki might crumble after squandering her chance to serve for the title, she hit a pinpoint backhand to break straight back and secure the win.
"It was all going well at 5-0 in the second set, then she went for her shots and I was just so happy to get it done in the end," Wozniacki said.
"Well eight is my lucky number and I figured if I was ever going to beat her it would be today and I just went out there and did my best."
It caps a resurgent 16 months for Wozniacki who, in that time, has climbed from 74th in the world to third after injury and poor form saw her slide down the rankings.
Despite the disappointment in defeat for the evergreen Williams, reaching the final in Singapore caps a resurgent 12 months of her own.
After reaching the final at 37 years of age -- the oldest woman in history to do so -- she now finishes the year ranked No. 5 in the world, her best since 2010.