The nanocomposite polymer electrolyte [x (85 PVA: 10 PPy: 5 KI: I2:15 EC: 15MPII: 10 TiO2) for x = 5, 10, 15 Gy γ-ray irradiation] is prepared using the solution casting technique. Exposure of γ-ray irradiation enhanced the amorphous nature of the polymer electrolyte, is confirmed by XRD. The 15Gy γ-ray-irradiated nanocomposite polymer electrolyte has higher electrical conductivity and minimum activation energy (0.664 kJ mol−1). The EIS measurement reveals that the 15Gy γ-ray-irradiated nanocomposite polymer electrolyte incorporated DSSC shows lower Rct1 and Rct2 values at the counter electrode/electrolyte and photoanode/electrolyte interface, respectively. An outstanding performance is observed in the fabricated DSSCs using 15 Gy γ-ray-irradiated nanocomposite polymer electrolyte with a short circuit current density of 12.602 mA cm−2, an open-circuit voltage of 0.711 V, a fill factor of 0.535, and a photovoltaic conversion efficiency of 4.79% under the light intensity of 100 mW cm−2.