Calcium fortification of plant proteins such as soybean 11S globulin (glycinin) represents a promising nutritional strategy but often compromises protein functionality due to calcium-induced aggregation. To mitigate this, we developed a two-step process: first preparing high-calcium glycinin (14.18 mg/g), followed by hot-alkali (HA) treatment to enhance its properties. While initial calcium loading reduced protein solubility by 40.84%, subsequent HA modification effectively restored it to 93.29% by inducing structural reconformation, including tertiary structure unfolding and increased α-helix content. These changes significantly improved the emulsifying, foaming, and gelling properties of glycinin. Moreover, HA treatment increased the calcium-binding capacity by 2.2-fold compared to the native protein. This study demonstrates that hot-alkali modification is a highly effective method for producing a multifunctional soy glycinin ingredient with superior techno-functional performance and enhanced nutritional potential for fortified foods.