La‐ and Sn‐cosubstituted lead zirconate titanate () ceramics are synthesized using a solid‐state reaction route. These (PLZST) ceramics in pure form are found to exist in dual phase () and single phase (Cc) depending on the amount of La/Sn cosubstitution. PLZST ceramics exhibit thin P–E loops with enhanced polarization when measured at 393 K. Olsen cycle method is used to estimate the pyroenergy harvesting abilities of the samples under study. The estimated maximum energy storage density for PLZST () ceramics at 393 K is 1.16 J cm−3 [efficiency (η) > 96%]. The PLZST ceramics exhibit a remarkable hardness of 9.08 GPa. These results indicate that PLZST ceramics with excellent multifunctional properties are potential candidates in the field of electroceramic devices.