Currently, biodiesel stands as a sustainable and renewable alternative to depleting fossil fuels like petro-diesel. The widespread adoption of biodiesel production holds promise for enhancing environmental quality by reducing greenhouse gas emissions and promoting societal-economic development. In line with this, our research has focused on synthesizing biodiesel from the novel and edible seed oil of Niger oil, utilizing a green catalyst derived from the calcination of banana peel ash at 600 °C for 4 h. Advanced characterization techniques, including X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Diffraction X-Ray (EDX), Thermogravimetric Analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), and Fourier-transform Infrared Spectroscopy (FT-IR), were employed to assess the catalytic activity of the catalyst. Under optimized reaction conditions a methanol-to-oil molar ratio of 15:1, catalyst loading of 1% (wt.%), reaction time of 4 h, and temperature of 70 °C we achieved a commendable biodiesel yield of 92.30%. Gas Chromatography (GC) analysis of the biodiesel revealed four distinctive peaks corresponding to methyl esters. Results from Fourier-transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) confirmed the presence of methyl esters in the biodiesel sample. Additionally, the fuel properties of the biodiesel, including density (0.904 kg/m3), kinematic viscosity (4.56 cst), cloud point (3 °C), pour point (2.8 °C), and flash point (149 °C), complied with international ASTM D standards. In conclusion, Niger biodiesel emerges as a highly promising, eco-friendly, reusable, and cost-effective feedstock for biodiesel production, thereby holding significant potential for advancing sustainable energy solutions.