We report a comprehensive theoretical investigation of the mixed boron and magnesium B18Mg6 0/+/2+ clusters, revealing their structural robustness across neutral, cationic, and dicationic states. All charge states exhibit a spheroidal geometry, indicating that the cluster maintains its framework during sequential charge–discharge processes. The dication B18Mg62+ possesses a stabilized π electron configuration with a HOMO–LUMO gap of 2.1 eV, while the cationic and neutral forms arise from controlled electron addition, leading to distinct spin states. The hydrogen storage performance of B18Mg6 0/+/2+ is assessed across different charge states, demonstrating a large adsorption of up to 24H2 molecules (12.44 wt%) at 0K. Under practical conditions, being 70 MPa type IV compressed hydrogen storage tanks, room temperature, the doubly charged cation B18Mg62+ achieves a maximum uptake of 21H2 molecules (11.06 wt%), and charge-assisted desorption enables complete H2 release below 3 MPa at room temperature. This charge-controlled desorption allows a full hydrogen release under milder pressure swings than conventional temperature/pressure-swing or chemical storage methods.