The present study shows the synthesis of silver nanoparticles (Ag NPs) using a methanolic and aqueous extract of R. stricta. UV–visible spectroscopy, energy-dispersive X-ray diffraction (EDX), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR) techniques were used to further characterize the Ag NPs. UV–visible spectra give surface Plasmon resonance (SPR) at 490–560 nm for Ag NPs. The existence of various functional groups existing in biomolecules capping the nanoparticles is indicated by the FTIR spectrum. The average size of Ag NPs is 20–35 nm, while the shape is spherical, as confirmed by FESEM. The plant extract and Ag NPs were evaluated against their antioxidant, antibacterial (Staphylococcus aureus, E. coli, and Salmonella typhi), and antifungal activities (Trichophyton longifusis, Candida albican, and Fusarium solani), where the Ag NPs exhibited superior activity versus the plant extract. The inhibitory effect of NPs against the tested strain was more effective as compared to the crude extract of R. stricta.