Oryza sativa L. is one of the main staple crops in the South Korea. While rice production has remained stable over the past decades, rice consumption has gradually declined, leading to a rapid stockpile in rice inventory. Conventional rice storage methods often fail to preserve functional properties and long-term stability, necessitating innovative processing techniques. Methods: To address this issue, we developed a grain stabilization technique (GST) to enhance the functionality and shelf life of white rice (WR), brown rice (BR), and rice germ (RG). The GST process was conducted in a single-batch system, integrating a controlled temperature cycle (65~85 °C) with 60 rpm rotation, far-infrared (26,400 W/m2), and ultraviolet (254 nm, 60,880 J/m2) irradiation in an enclosed chamber equipped with an exhaust system for moisture, odor, and impurity removal. The process was followed by air drying (25 °C, 15 h) to ensure stability. Results: The GST significantly increased resistant starch content in BR and WR by 214% and 27%, respectively, but not in RG. Additionally, GST enhanced the contents of campesterol, stigmasterol, β-sitosterol, and octacosanol in BR and RG, but not significantly in WR. Furthermore, this technique markedly reduced moisture content, acidity, and bacterial counts over a 90-day storage period and kept mycotoxin levels within safe limits in WR, BR, and RG. GST also altered the microstructures of WR and BR, indicating gelatinization and amorphization of starch granules. Conclusions: These findings contribute to advancing food science by presenting GST as a transformative method to extend shelf life and improve the nutritional profile of rice, aligning with global efforts to reduce food waste, improve dietary health, and develop sustainable food processing technologies.