Playing her trademark pink ball in the final round, the 21-year-old Creamer closed with a bogey-free 6-under 66 for a 16-under 200 total.
After holing a 5-foot putt on the par-4 18th for her third straight birdie, Creamer pumped her arms in the air and smiled as the crowd cheered.
The putt was set up by an aggressive second shot from 165 yards, over the pond and onto the green, where it bounced twice and rolled to 5 feet. Jang just missed the green from 153 yards, leaving the door open for Creamer.
With Creamer watching closely, Jangs 35-foot birdie putt from the fringe curled left. Creamer then calmly made her birdie.
Jang, seeking a wire-to-wire victory, closed with a 69.
Michelle Wie shot a 6-over 78 to finish 20 strokes behind Creamer. At 4-over 220, Wie tied for last among the 74 players who made the cut.
Lindsey Wright finish third at 14 under, birdieing three of the final five holes for a bogey-free 67.
Annika Sorenstam (68) followed at 12 under, a week after winning the season-opening SBS Open at Turtle Bay last week for her 70th LPGA Tour title.
She birdied three of her first five holes to make the turn at 11 under, two strokes behind Jang, but had a costly double bogey on No. 10, followed by three straight birdies.
The 37-year-old Sorenstam has proven shes healthy and confident again after coming off an injury-shortened season in 2007 where the Swedish star was winless for the first time since her rookie season in 1994.
Karen Stupples (66) and Minea Blomqvist (69) tied for fifth at 11 under.
Conditions at Ko Olina were balmy and calm for a third day, forcing players to go low.
Creamer, who suffered from flu-like symptoms earlier this week, made her move late, and early. She birdied Nos. 1 and 3 to put catch Jang for the lead. Jang regained the lead at 13 under with a birdie on No. 6.
Creamer parred 10 straight holes before her birdie flurry. She kneed her putter after just missing a 15-foot eagle putt on the par-5 14th. Jang earlier missed her 23-footer for eagle.
The American shook her fist after sinking a 15-foot birdie putt that pulled her within a stroke of Jang with two strokes to play. Creamer then made a 12-foot putt on No. 17 for a share of the lead.
Creamer finished third on the money list last year with 13 top-10 finishes, including two victories.