It　is　an　urgent　need　to　develop　lead-free　piezoelectric　energy　harvesters　(PEHs)　to　address　the　energy　dilemma　and　meet　environmental　protection　requirements.　However,　the　low　output　power　densities　limit　further　promotion　of　lead-free　PEHs　for　use　in　daily　life.　Here,　an　entropy-increasing　strategy　is　proposed　to　achieve　an　increased　output　power　density　of　819　mu　W/cm(3)　in　lead-free　potassium　sodium　niobate　(KNN)-based　piezoceramics　by　increasing　the　configuration　entropy　and　realizing　nearly　two　times　the　growth　compared　with　low-entropy　counterparts.　Evolution　of　the　energy-harvesting　performance　with　increasing　configuration　entropy　is　demonstrated　systematically,　and　the　excellent　energy-harvesting　properties　achieved　are　attributed　to　the　enhanced　lattice　distortion,　the　flexible　polarization　configuration,　and　the　high-density　randomly　distributed　nanodomains　with　the　entropy-increasing　effect.　Moreover,　excellent　vibration　fatigue　resistance　and　variable　temperature　output　power　characteristics　were　also　realized　in　the　PEH　prepared　by　the　proposed　entropy-increasing　material.　The　significant　enhancement　of　the　comprehensive　energy-harvesting　performance　demonstrates　that　the　construction　of　KNN-based　ceramics　with　high　configuration　entropy　represents　an　effective　and　convenient　strategy　to　enable　design　of　high-performance　piezoceramics　and　thus　promotes　the　development　of　advanced　PEHs.