The effective transformation of solar photons into electrical energy using innovative and environmentally friendly materials is a key focus in renewable energy research. In this study, chalcogenide perovskite CaZrS3 is employed as the absorber layer for solar photovoltaic applications, coupled with ZnO as ETL and Cu2O as HTL. A comprehensive theoretical investigation is conducted by utilizing the SCAPS-1D simulator to identify the most efficient photovoltaic device configuration. The performance of the solar device is evaluated by varying different parameters, including HTLs, thickness and defect density in the absorber layer, interface defect densities, CBO and VBO at ETL/PSK and PSK/ETL interfaces, series and shunt resistances, and the back contacts work function. The optimized solar device achieves a PCE of 21.25% with outstanding PV properties. This research highlights the potential of CaZrS3 as a chalcogenide absorber material for photovoltaic applications, demonstrating it as an effective and eco-friendly alternative.