Implant-associated infections (IAIs) persist as a critical complication in biomaterial transplantation, driven by rapid microbial colonization, biofilm encapsulation, and escalating antibiotic resistance. Conventional antibiotic-based treatments and passive antimicrobial coatings often fail to achieve long-term infection control due to limited biofilm penetration, localized cytotoxicity, and active agent depletion. To overcome these limitations, piezoelectric nanocomposite coatings utilize a dynamic, stimulus-responsive framework that converts physiological mechanical forces or external ultrasound into localized electrical signals. These surface-bound electric fields systematically mitigate bacterial adhesion, eradicate mature biofilms via targeted reactive oxygen species (ROS) generation, disrupt microbial metabolic pathways, and favorably modulate the peri-implant immune microenvironment while supporting host tissue repair. This review evaluates the material design principles and classifications of inorganic, organic, and hybrid piezoelectric nanocoatings. We detail their multifaceted antibacterial mechanisms and trace their therapeutic potential in orthopedic and dental implants, as well as wound management. Lastly, we analyze current engineering bottlenecks to chart a clear trajectory for their clinical translation.