<p>Polyvinylidene fluoride (PVDF) is one of the most widely studied polymers for the development of film capacitors with high energy density. However, it is still challenging to modulate the polarization hysteresis phenomenon of PVDF in a simple and effective way to achieve a significant increase in energy density. In this work, a low-loss amorphous polymer poly(methyl methacrylate) (PMMA) was introduced as a reinforcing phase to be blended with PVDF to form a matrix. The dielectric and energy storage performance of PVDF is improved by integrating the high dielectric property of barium titanate (BaTiO₃) with the low hysteresis property of PMMA. PMMA/PVDF-BaTiO₃ nanocomposites were prepared by spin-coating process. It was shown that the PMMA/PVDF-BaTiO₃ nanocomposites had a thin and flat macroscopic structure and a uniform and dense microstructure. The optimum dielectric constant of the nanocomposites was 12.9 at 100&#xa0;Hz, and the optimum energy density was maximized to 6.5&#xa0;J/cm³. Compared with the PVDF/PMMA composites, the dielectric and energy storage performance were significantly improved under the same conditions. This work provides a simple and effective strategy for obtaining polymer nanocomposites with high energy density and with potential as flexible dielectric substrates for film capacitors.</p>