This work describes the practicability of utilizing bentonite clay as a cheap and raw support for heterogeneous catalyst development. In the current research, ammonium persulfate (APS) impregnated bentonite heterogeneous catalyst was designed for the conversion of waste cooking oil to biodiesel. The fabricated catalyst was analyzed by various instrumental techniques (FTIR, TGA, BET, SEM, XRD, and EDX) to study its various physiochemical properties. It was identified that the clay supported heterogeneous catalyst executed an excellent activity for waste cooking oil conversion as providing maximum biodiesel yield of 93% at optimal reaction conditions (reaction temperature 75℃, oil/methanol molar ratio, 1 : 10; catalyst amount, 2.5 wt%; stirring rate, 600-rpm in 3.5 hr reaction time). Gas chromatography mass spectroscopy (GCMS) analysis confirms the successful conversion to biodiesel. Similarly, the various physiochemical characteristics of the synthesized biodiesel meet the international standard of American (ASTM6751) and European Union (EU-14214). Moreover, the designed acid catalyst showed catalytic activity for up to eight consecutive runs demonstrate its good reusability.