This study presents the synthesis of CuO-TiO₂-ZnO (CuTiZn) ternary nanocomposite via the use of Kenger (Gundelia tournefortii) gum extract as a biogenic reducing and stabilizing agent. The synthesized CuTiZn nanocomposite was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). XRD analysis confirmed the formation of a CuO-TiO₂-ZnO nanocomposite with a monoclinic crystal structure. SEM images revealed spherical, well-dispersed particles, whereas FTIR spectra indicated the presence of functional groups from the Kenger gum extract involved in the reduction process. Biological applications, including antibacterial activity against both gram-positive and gram-negative bacteria, were evaluated, yielding promising results. The antimicrobial activity of the biosynthesized ternary nanocomposite was evidenced by the formation of inhibition zones ranging from 13.5 to 18 mm in diameter against both gram-positive and gram-negative bacteria. The antioxidant properties were assessed via DPPH radical scavenging assays, which revealed an inhibition rate of approximately 34% at a concentration of 12.5 mg/mL. In anticancer activity assays, the CuTiZn nanocomposite exhibited an IC₅₀ value of 201.1 µg/mL against the MCF-7 human breast cancer cell line. These findings suggest that the biosynthesized CuTiZn nanocomposite possesses promising antimicrobial, antioxidant, and anticancer properties, highlighting their potential for biomedical applications. This study, for the first time, uses the green synthesis of CuTiZn ternary nanocomposite using Kenger (Gundelia tournefortii) gum agent. This eco-friendly approach not only minimizes toxic reagents but also enables the production of multifunctional nanocomposite with superior antibacterial and cytotoxic performance due to the synergistic effects of the three metal oxides.