Background: The timely administration of platelet transfusions is critical for patient survival, and the clinical demand for platelet transfusions has been steadily increasing. However, platelet storage lesions (PSLs) that develop during in vitro preservation exacerbate these shortages. The PSL is significantly influenced by various factors, including temperature, gas composition, and buffering systems. Strategies to mitigate PSLs and improve platelet storage have been actively explored in recent years. Objectives: This study aimed to investigate whether elevated carbon dioxide (CO2) levels improve platelet quality and functionality during storage. Methods: Platelet concentrates from 28 donors were stored under control or 3% CO2 conditions at 22 ± 2 °C for up to 7 days. Platelet quality was evaluated through scanning electron microscopy, adhesion, aggregation, clot contraction, activation, apoptosis assays, blood gas, adenosine triphosphate, metabolomics analyses, and in vivo thrombosis and survival tests. Results: Our findings indicate that increasing the CO2 concentration in the storage environment mitigates PSLs and improves platelet quality. Conclusion: Our study highlights the potential benefits of utilizing a high CO2 storage environment to improve platelet preservation, offering a promising method to address clinical platelet shortages.