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Electric-field control of magnetic resonance has application potential in the design of low-power, compact, high-frequency magnetoelectronic devices, such as microwave filters and circulators. To date, this work has exploited low-loss ferrite materials mechanically coupled to piezoelectric substrates. However, traditional ferrites typically require lattice-matched substrates and extreme growth conditions to produce high-quality material, making on-chip integration a significant challenge. Here, we demonstrate indirect electric-field control of ferromagnetic resonance (FMR) in devices that integrate the low-loss (α = (3.98±0.22) × 10^-5), molecule-based, room-temperature ferrimagnet vanadium tetracyanoethylene (V[TCNE]_x~2) with PMN-PT piezoelectric transducers. The ultra-narrow FMR linewidth of V[TCNE]_x allows us to demonstrate tuning of more than 6 times the resonant linewidth by applying 13.3 kV/cm across the PMN-PT transducer. A systematic analysis of the Gilbert damping in unstrained and strained V[TCNE]_x films shows no change in damping, α. Combined with the demonstrated ability to pattern V[TCNE]_x at micron-length scales on a wide variety of substrates, these results herald a new paradigm for on-chip voltage-tuned microwave devices.