Li, who turns 32 next month, lost Australian Open finals to Kim Clijsters in 2011 and to Victoria Azarenka last year. In between, she won the 2011 French Open to become the first Chinese woman to win a major.
In both her previous finals at Melbourne Park, Li won the first set but went down in three. Against Azarenka last year, she stumbled and twisted her ankle, and needed a medical timeout in the third set after hitting her head on the court.
She had no such trouble against No. 20-seeded Cibulkova this time after winning the first set in a tiebreaker.
Li held up both thumbs, and held back tears, as she left the court. She went immediately to the side of the court to shake hands with her coach Carlos Rodriguez in the stands.
The first set lasted 70 minutes, including two exchanges of service breaks and some nervous moments for Li, who was struggling with her first serve.
The diminutive Cibulkova, one of the shortest players ever to reach a Grand Slam final at 1.61-meters (5-feet-3), had four wins over Top 20 players in the tournament, including a fourth-round upset of third-seeded Maria Sharapova and a straight-sets semifinal trouncing of No. 5 Agnieszka Radwanska.
Li opened with wins over the two youngest players in the tournament, then saved a match point in her third-round win over Lucie Safarova. In the semifinals, she held off 19-year-old Canadian Eugenie Bouchard, and never had to face a player ranked in the top 20 en route to the final.
"Finally I got her,'' Li said as she put a hand on the Daphne Akhurst trophy for the first time as Australian Open women's champion. "Last two times was very close.''