High-dielectric-constant (high-k) polymer–ceramic composites with low-level dielectric loss are expected to enable excellent energy storage. However, high conductivity and high dielectric loss often occur simultaneously with high dielectric constant. To obtain a high dielectric constant but with low conductivity and low dielectric loss, in this work, we studied the ternary polyvinylidene fluoride (PVDF)/La2TiO5/V2C dielectric composite system, which takes advantage of the synergistic effect between the high content (0 wt.% to 40 wt.%) of pseudo-perovskite filler La2TiO5 and the low content (2 wt.%) of highly conductive two-dimensional filler V2C. Comparisons with the binary PVDF/La2TiO5 composite system revealed that the ternary PVDF/La2TiO5/V2C composite dielectric system enabled balance and optimization of the comprehensive electrical properties of the composite material. Significantly elevated permittivity as well as depressed low-level dielectric loss were obtained in the ternary composites. The optimized ternary composite with 40 wt.% La2TiO5 and 2 wt.% V2C exhibited high dielectric constant of 47 and low dielectric loss of 0.17 at 1 kHz. This work might enable facile fabrication of promising composite dielectric materials based on this excellent synergetic filler strategy.