Dye-sensitized solar cells (DSSCs) have garnered considerable attention due to their cost-efficiency, expandability, and potential for renewable energy production using small-scale materials and natural organic dyes in harnessing solar radiation for power generation. In this study, Red Dragon fruit (Hylocereus polyrhizus) extract (RDFD) was used as a dye sensitizer for Cu@TiO2 photoanode with waste chicken feather biocarbon as a counter electrode. Scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy were used to characterize the photoanode in terms of its surface morphology and elemental composition, crystalline phases, functional groups with bond formation, and optical properties, respectively. Comparative experiments were conducted to assess the effects of varying TiO2:Cu mass ratios on the photovoltaic parameters namely short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and cell efficiency (ɳ). The highest comparative photovoltaic performance with Jsc = 0.958 mA∙cm–2, Voc = 785.630 mV, FF = 0.669, and ɳ = 0.503% was achieved at annealing temperature (AnT) = 350 °C, annealing time (AT) = 1 h, and dye-soaking time (DST) = 1 h using 63.5 μm TCu1.5 photoanode. Parametric analysis was further carried out to investigate the influence of AnT, AT, and DST on the photovoltaic parameters. Cell efficiency optimization using Box-Behnken design of response surface methodology showed a remarkable ɳ = 2.19% at AnT = 418.53 °C, AT = 1.98 h, and DST = 1.03 h. The results of this study confirmed the successful integration of Cu@TiO2 photoanode and RDFD sensitizer and thus marked substantial advancement in sustainable energy solutions by creating unparalleled and eco-conscious photovoltaic devices.