The use of plants to produce metallic nanoparticles is an emerging sustainable approach that enables the fabrication of nonmaterials with unique physical, chemical, and biological features. In this study, aqueous extracts of leaves of Sauropus androgynus were used for the first time as reducing and stabilizing agents in the synthesis of silver and copper nanoparticles. The aqueous extracts were prepared by subjecting the leaves of Sauropus androgynus to boiling, followed by reaction with the precursor solution. The production of silver and copper nanoparticles was evident by the change in colour of the reaction mixture. The produced nonmaterial’s were purified, dried, and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The Fourier transform infrared spectroscopy results suggest that hydroxyl, carbonyl, and amine groups play major roles in the reduction and stabilization of the nanoparticles. Meanwhile, the X-ray diffraction analysis showed the crystalline nature of the fabricated nanomaterials, whereas scanning electron microscope images demonstrated the production of irregular nanoparticles of various sizes (10–100 nm). Additionally, antibacterial and free radical scavenging assays were performed to establish the biological potential of the synthesized nanomaterials. Notably, copper and silver nanoparticles showed significant antibacterial activity against all the tested bacterial strains. Also, the antioxidant property of the nanoparticles was demonstrated by the DPPH assay, which showed that the CuNPs and AgNPs exhibited free radical scavenging activity. Thus, this study demonstrated the ability of leaf extracts to synthesize CuNPs and AgNPs, which can be used in various applications, such as medicine, pharmaceuticals, and environmental science.