<p>In ferroelectric energy storage systems, energy storage density and efficiency are primarily determined by polarization characteristics and the applied electric field. Layered perovskite thin films, such as CaBi₂Nb₂O₉ (CBNO), inherently exhibit low remanent polarization (<i>P</i>_r), making them attractive candidates for energy storage applications. Their Aurivillius-type structure also offers excellent leakage current characteristics and fatigue resistance. In this study, we investigated the effects of La doping on the structural, ferroelectric, and energy storage properties of CBNO thin films fabricated by pulsed laser deposition. La doping at 10&#xa0;mol% led to enhanced crystallinity and structural alignment, which likely contributed to the observed improvement in ferroelectric performance, including a <i>P</i>_r of 12.3 µC/cm². It also achieved the highest recoverable energy density (<i>U</i>_re) of ~ 91.7&#xa0;J/cm³ and an energy storage efficiency of 82.9%, attributed to its superior leakage current characteristics. Significantly, the thin film demonstrated excellent fatigue resistance, maintaining stable energy storage performance with minimal change in <i>U</i>_re after 10¹² switching cycles. These findings reveal the potential of La-doped CBNO thin films, particularly at 10&#xa0;mol% doping, as promising candidates for next-generation high-efficiency and durable energy storage devices.</p>