For photovoltaic (PV) applications, the earth‐abundant and non‐hazardous Kesterite Cu2ZnSnS4 (CZTS) is a possible substitute for chalcopyrite copper indium gallium selenide (CIGS). This research offers insight into the most innovative method for improving the performance of Kesterite solar cells (SCs) by using CuSbS2 back surface field (BSF) and Ag2S and In2Se3 as buffer layers, focuses on aligning energy bands, reducing non‐radiative recombination, and improving open‐circuit voltage (Voc). The proposed cells are Ni/CuSbS2/CZTS/In2Se3/ITO/Al and Ni/CuSbS2/CZTS/Ag2S/ITO/Al by adding interfaces. The optimized CZTS SCs with In2Se3 achieve a short‐circuit current density (Jsc) of 30.274 mA/cm2, fill factor (FF) of 89.15%, power conversion efficiency (PCE) of 31.67%, and Voc of 1.173 V. With the Ag2S buffer layer, PCE is 31.02%, FF is 88.61%, Jsc is 30.245 mA/cm2, and Voc is 1.157 V. These results depict the potential of CZTS‐based SCs with improved performance compared with conventional structures.