Abstract Biodiesel synthesis requires both feedstock diversification and sustainable heterogeneous catalyst precursors to impact its viability. This study is focused on the development of a heterogeneous catalyst from moringa leaves as a sustainable precursor for biodiesel production. The catalyst was prepared by facile calcination at 500 °C for 2 h and used directly in transesterification reaction with oil and methanol to synthesize biodiesel. The catalyst structural properties, surface morphology, and mineral constituents were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectrometry of X-rays (EDS). The results show that inorganic carbonate minerals of dolomite, calcite, and (K2Ca(CO3)2) were obtained after calcination and these minerals promoted the transesterification reaction. Hence, under reaction conditions of 6:1 methanol/oil molar ratio, 120 min, 65 °C, and 6 wt% catalyst dosage, 86.7% FAME yield was observed. Consequently, the investigation of the ASTM standard for quality assessment indicates that the synthesized biodiesel meets the specification for commercial biodiesel. The catalyst could be reused in three cycles of the experiment.