This work describes the practicability of utilizing bentonite clay as a cheap and raw support for heterogeneouscatalyst development. In the current research, ammonium persulfate (APS) impregnated bentonite heterogeneouscatalyst was designed for the conversion of waste cooking oil to biodiesel. The fabricated catalyst was analyzed byvarious 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 oilconversion as providing maximum biodiesel yield of 93% at optimal reaction conditions (reaction temperature 75 oC,oil/methanol molar ratio, 1 : 10; catalyst amount, 2.5 wt%; stirring rate, 600-rpm in 3.5 hr reaction time). Gas chromatographymass spectroscopy (GCMS) analysis confirms the successful conversion to biodiesel. Similarly, the variousphysiochemical 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 consecutiveruns demonstrate its good reusability.