Sustainable energy technologies require the development of sustainable composites using novel methods and materials with a minimal environmental impact. Piezoelectric effect-based mechanical energy harvesting (MEH) and sensing offer great potential as a sustainable technology for low-grade mechanical energy harvesters and self-powered sensors. Herein, we utilize ZnO to functionalize the delignified wood surface for MEH and vibration sensing applications, where wood act as robust support to well adhered piezoelectric ZnO nanoparticles. This surface functionalization strategy is a reasonable substitute for the bulk ZnO films, which offer optimal utilization of active material at relatively low content. The wood/ZnO composite device is utilized for vibration sensing and MEH. The device (25 cm2) resulted in a peak to peak output voltage of ~15 mV and a peak to peak current of ~2.2 nA under the influence of mechanical vibrations from the periodic motion of a linear motor operating at the acceleration of 50 ms-2. The scalable fabrication approach signifies the practical use of wood-based composites for piezoelectric mechanical energy harvesting.