The expansion of smart healthcare and wearable electronics has intensified the need for fabric-based sensors that integrate conformally with the human body for continuous bio signal monitoring. However, the heavy reliance of conventional devices on external batteries remains a major obstacle to commercialization, necessitating the development of flexible piezoelectric energy harvesters that convert biomechanical energy into sustainable power. Here, we present a highly flexible and wearable piezoelectric energy harvester (PEH) fabricated by a screen-printing of BaTiO₃ nanoparticlePDMS composites onto a fabric substrate. An optimized piezo-ceramic filler concentration of 70 wt% yielded a peak output voltage of 0.52 V and a current of 40 nA under the mechanical bending deformations. The fabricated PEH demonstrated exceptional mechanical and electrical stability, showing no performance degradation of over 5,000 repetitive bending cycles. These results indicate that a PEH can function as a stable self-powered source within complex clothing environments, offering a promising pathway for next-generation autonomous wearable sensor systems.