The global transition in energy consumption patterns driven by the depletion of fossil fuel reserves, rapid population growth, and increasing environmental pollution has faster the exploration for renewable and ecological energy substitutes. Among these, biodiesel has materialized as a capable candidate due to its carbon-neutral profile, environmental compatibility, and potential as a cleaner alternate for conventional petroleum-based diesel. In this study, the performance of iron(II)-doped zinc oxide (Fe(II)-ZnO) nanocatalyst was investigated for biodiesel production from Jatropha curcas oil. The nanocatalyst was synthesized and characterized using Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and zeta potential analysis. AFM analysis revealed pronounced surface topography with elevated features reaching up to 50 nm in height. The formation of Zn–O and Fe–O bonding was affirmed through FTIR spectra, while XRD analysis demonstrated the presence of crystalline phases corresponding to Fe₂O₃ and ZnO, with the most intense diffraction peak observed at 2θ = 35.8777°. Zeta potential measurements indicated moderate colloidal stability with a measured value of –4.01 mV. The Jatropha curcas oil used in the transesterification process possessed a density of 909 kg/m³ at 25 °C, an acid value of 1.20 mg KOH/g, and a viscosity of 25.63 mm²/s.. Transesterification was carried out under optimized reaction conditions, comprising a methanol-to-oil molar ratio of 12:1, reaction temperature of 50 °C, catalyst loading of 2% Fe(II)-ZnO, and a reaction time ranging from 10 to 180 minutes. The produced biodiesel exhibited a density within the ASTM D6751 standard specifications. While the flash point was slightly elevated making it suitable for blending with petro-diesel the viscosity remained marginally higher than standard diesel fuel.