Due to its unique properties and advantageous traits, zinc oxide has garnered significant attention in recent years for the green synthesis of ZnO nanoparticles (ZnO‐NP). This paper is focused on the synthesis of ZnO‐NPs mediated by Adiantum capillus‐veneris L. leaf extract and assesses their potential biological activities. In this study, ZnO‐NP is synthesized using A. capillus‐veneris L. leaf extract. The synthesized nanoparticles are characterized using, UV–vis spectroscopy, energy‐dispersive X‐ray spectroscopy (EDX), (SEM) scanning electron microscopy, X‐ray diffraction (XRD), and Fourier transform infrared (FT‐IR) spectrophotometry. The antibacterial, antifungal, anti‐inflammatory, and antioxidant properties of the formulated ZnO‐NPs are also inspected. The UV–vis, XRD, SEM, EDX, and FTIR confirmed the formation and purity of synthesized ZnO‐NPs. The ZnO‐NPs exhibit efficient antimicrobial potency against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Aspergillus niger, and Aspergillus fumigatus. Gram‐positive bacteria, particularly S. aureus, are more susceptible to ZnO‐NPs, with the largest inhibition zone of 32 mm. In contrast, E. coli and P. aeruginosa display smaller inhibition zones of 25 and 27 mm respectively. Anti‐inflammatory tests show that ZnO‐NPs have a significant anti‐inflammatory effect against egg albumin and bovine serum albumin denaturation, possess low toxicity on erythrocytes, and are highly hemocompatible.