With the U.S.-partisan crowd on their feet, Garcia closed out the victory by striking out Yu Chieh Kao. The California fans yelled "USA! USA."
The teams shook hands before California celebrated, then invited Taiwan to accompany them on the customary victory lap around Lamade Stadium on a sun-splashed afternoon.
They reveled in the United States' fifth straight Little League championship.
The latest win looked in doubt early. Wen Hua Sung and Chin Ou hit back-to-back homers in the third to give Taiwan a 3-0 lead.
California scored a run in the third before surging ahead in the fourth. Seth Godfrey drove in a run on a sacrifice fly before Nick Conlin scored on a wild pitch.
Even Vice President Joe Biden, who attended the game, was impressed, standing and clapping as his three granddaughters looked on.
Later, Taiwan walked slugger Luke Ramirez with two outs to bring up Graft. The 12-year-old second baseman hit a 1-1 pitch to right to score Andy Rios from third.
California added two runs in the fifth, more than enough cushion for Garcia.
The boys threw their gloves high in the air after Kao struck out, then gathered near the mound and fell into a pile on the ground.
Ou, who started for Taiwan, baffled California early with breaking balls before the team rallied in the fourth inning.
California didn't homer Sunday, though the club followed through on manager Oscar Castro's philosophy to hit line drives, not the long ball.
Taiwan's coaches declined to speak with reporters afterward, instead choosing to lead their players across the field back to their dorms, with equipment bags in hand.
They walked right past giddy California boys on their hands and knees, scooping up bags of infield dirt as a memento of their big win.