The Giants made the playoffs in 2014 as a Wild Card team, then defeated the Pirates in the NL Wild Card Game. In the NLDS against the Washington Nationals, Casilla made three scoreless appearances, earning two saves as the Giants defeated Washington in four games. Against the Cardinals in the NLCS, he pitched scoreless innings in three of the first four games, earning saves in Game 1 and Game 4. He entered a tied Game 5 in the top of the ninth and loaded the bases by giving up a walk and a couple of hits, but Jeremy Affeldt got Oscar Taveras to ground out to end the inning with no runs scoring, and Travis Ishikawa homered in the bottom of the inning to give the Giants a 6–3 triumph, clinching a 4–1 series victory. He made only two appearances in the World Series against the Kansas City Royals, recording an out apiece in Games 2 and 3, both losses. For the third time in his career, Casilla became a World Series champion as the Giants defeated Kansas City in seven games.