This research examines mechanical finishing and digital printing methods for imparting antibacterial properties to denim fabrics. It evaluates the use of plant-based nanoemulsions, which are nontoxic and environmentally friendly, as alternatives to synthetic antimicrobial agents. This finishing technique enhances the functional properties of denim fabrics, enabling them to be used for longer periods without requiring frequent washing. Additionally, it prevents the formation of odor and microbial growth during consumer use. Two types of nanoemulsions, namely, Karanja and Shankapushpi, were derived from plant-based herbs combined with coconut oil and curry leaves. The nanoemulsions were characterized for their thermal stability, particle size, and percentage add-on. The finished denim fabrics were assessed for their antimicrobial properties using Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Furthermore, the durability and skin safety of the finished fabrics were tested. The antimicrobial efficacy of Karanja nanoemulsion before washing was 99.73% (S. aureus) and 99.74% (E. coli), and for Shankapushpi, it was 99.77% (S. aureus) and 99.73% (E. coli). For digitally printed denim, no increase in bacterial growth was observed after 24 h. After washing, only a marginal reduction in the antibacterial efficacy (>99.2%) of the finished denim fabrics was observed, demonstrating the durability of the finish. In vitro cytotoxicity assessments demonstrated a cell viability of >70%, indicating acceptable cytotoxicity of the denim fabric and safety on the skin. Fourier transform infrared spectroscopy (FT-IR) analysis revealed the presence of a triple-bond carbon at 2105 cm–1 and fatty acids at 3006 cm–1 in both the nanoemulsions, Karanja and Shankapushpi, which are responsible for the antimicrobial property. This research suggests that denim fabrics can be treated with durable antibacterial properties using sustainable, environmentally friendly, and biocompatible plant-based herbal nanoemulsions. The digital printing method that uses fewer resources demonstrated high precision in applying the nanoemulsion to the fabric and proved more efficient than mechanical methods. This research introduces innovative approaches to enhance denim fabrics by preventing unpleasant odors from microbial growth, disinfecting surfaces, and reducing the frequency of washing. These methodologies employ plant-based herbal treatments for the first time to enhance denim functionality, highlighting potential applications in sportswear and athleisure that prioritize freshness, durability, and sustainability. © 2026 The Authors. Published by American Chemical Society