This research studied about the synthesis of green and novel catalyst from waste materials for biodiesel production. An activated carbon (AC) material from palm seed cake (PSK) was soaked with zine chloride (ZnCl₂) and treated with sulfonic acid (SO₃H). The use of a sulfonated palm seed cake (SO₃H-PSK) derived catalyst for the transesterification/esterification of triglyceride (TG) in waste cooking palm oil (WCPO) has been demonstrated. The synthesized SO₃H-PSK catalyst was characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and Brunauer-Emmet-Teller (BET) method. To study the effects of methanol/oil mole ratio, amount of catalyst, and reaction time, the process of biodiesel production was optimized using a Box-Behnken design (BBD) approach with response surface methodology (RSM). As a result, the optimum reaction parameters found were 12:1 methanol/oil mole ratio, 1 wt.% of the SO₃H-PSK catalyst, and 4 min of reaction time. The synthesized biodiesel from WCPO meets the criteria for standard biodiesel (ASTM D-6751 and EN 14214). The heterogeneous catalyst demonstrates a promising and effective application for biodiesel process especially for feedstocks containing high free fatty acid (FFA) content.