A non-fluorinated polyimide film for flexible displays and electronics is presented in this study. The resulting film exhibited high total transmittance (>88%), low haze (<0.3), and a low yellowness index (<1.3), ensuring minimal visual distortion. It also demonstrates high mechanical robustness, delivering a Young’s modulus of 5.2 GPa. Environmental and mechanical durability were systematically evaluated to verify long-term reliability. After prolonged UV-B exposure for 72 h, the film retained its optical neutrality with negligible yellowing, indicating strong resistance to photo-induced degradation. Furthermore, cyclic folding tests revealed outstanding fatigue resistance, as the film withstood more than 1,000,000 folding cycles at a bending radius of 1.5 mm without cracks or creases. These results demonstrate that the developed PFAS-free polyimide film is a promising candidate for next-generation flexible device applications.