<p>The design and development of efficient catalytic systems for sustainable chemical reactions and transformations is an essential principle. In the present study, the synthesis and application of a magnetic nanocatalyst for biodiesel production from waste cooking oil via transesterification reaction were presented. The catalyst was prepared from silica-coated copper ferrite nanoparticles functionalized with amine groups (CuFe₂O₄@SiO₂-NH₂). The surface, structural, and functional group properties of the catalyst were carefully investigated using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrational sample magnetometry (VSM). Under the optimized conditions obtained (4&#xa0;wt% catalyst, 1:12 oil to methanol molar ratio, 65 °C) without the need for high energy consumption and advanced equipment, the catalyst showed significant efficiency in biodiesel production. The catalyst is rapidly recovered by applying an external magnetic field and can be reused over several cycles with little activity loss, demonstrating its stability and practical applicability. This study increases the knowledge on the structure–activity relationship of metal oxide-based nanocatalysts and their performance as reaction intermediates in green catalytic processes, thus promoting the development of sustainable energy conversion systems.</p>