The biogenic nanocomposite synthesis using a plant extract is rapid, simple, efficient, cost-effective, and eco-friendly. This study investigated selective pharmacological activities such as anticancer, antioxidant, and DNA cleavage activities of Solanum elaeagnifolium-mediated green synthesizing Ag-AgO-Ag2O nanocomposite. To the best of our knowledge, Solanum elaeagnifolium has been the first time used to synthesize Ag-AgO-Ag2O nanocomposites. The synthesized nanocomposites were explored by using UV-Vis diffuse reflectance spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and photoluminescence analyses. Anticancer activity of Ag-AgO-Ag2O nanocomposites was tested on lung cancer cell lines (A-549) and showed activity at the IC50 of 67.09 μg/mL. The maximum ABTS and DPPH scavenging activity were 25.78% and 20.86% at 100 µg/L, respectively. Moreover, Solanum elaeagnifolium-mediated green synthesized Ag-AgO-Ag2O nanocomposites also exhibited considerable DNA cleavage activity. These results assured that the synthesized Ag-AgO-Ag2O nanocomposites using Solanum elaeagnifolium leaves extract may have potential applications in biomedical engineering.