The synthesis of silver nanoparticles using phytochemicals has attracted significant attention in the field of nanotechnology because of their low cost and environmental friendliness compared to conventional methods. The synthesis of silver nanoparticles with antibacterial properties through chemical reduction using phytochemicals present in an aqueous extract of Harrisonia abyssinica fruit is reported in the current study. The synthesized nanoparticles were characterized using various techniques, including UV-Vis spectrophotometry, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The findings showed that the prepared silver nanoparticles were crystalline and spherical, and exhibited a strong absorption band at 420 nm due to the surface plasmon resonance (SPR) resulting from free-electron oscillations. The successful reduction of silver ions to form nanoparticles was indicated by a peak due to metallic silver at 3 keV in the EDX spectrum. The fabricated nanoparticles exhibited significant antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial strains. The antibacterial effect was more pronounced for Staphylococcus aureus (MIC = 5 µg/mL) than Escherichia coli (MIC = 10 µg/mL). The findings of the current study contribute to the field of nanotechnology by demonstrating a green approach to synthesizing silver nanoparticles with antibacterial properties using natural sources from plant materials.