Incorporating the active medium in a photonic crystal (PhC) structure enables a unique way to engineer the light–matter interaction, leading to the tunability of nonlinear optical responses. The nonlinear optical response of a nanometer-size nonlinear medium can be significantly enhanced by implementing a dielectric periodic structure that facilitates the confinement of light. Hereby, we demonstrated the band edge-assisted enhancement of optical nonlinearity in a one-dimensional polymeric PhC structure consisting of graphene quantum dots (GQD) as the active material. GQDs were synthesized through pulsed laser irradiation of toluene, and they were integrated into the alternative layers of polyvinyl carbazole (PVK) of a PVK/cellulose acetate PhCs. The lower-frequency photonic band edge is precisely tuned to match the excitation wavelength used for the nonlinear optical studies. The open-aperture Z-scan studies of the fabricated structure at 532 nm reveal a substantially enhanced nonlinear absorption property and optical limiting action. The enhanced nonlinear activity is attributed to the slow light effect at the photonic band edge, which improves the electron–photon interaction and, consequently, the local field of interacting laser pulses. The optical limiting threshold of the PhC structure incorporated with GQD is found to be ∼0.38 J/cm2, and it is superior to many reported benchmark values. Findings of the study open up avenues to realize nonlinear photonic devices such as optical limiters, on-chip integrated devices, and optical switches in the future.