A sample with a composition of 84 wt% MgH2-10 wt% Ni-2 wt% NaAlH4-2 wt% Ti.2 wt% CNT (named MgH2-10Ni-2NaAlH4-2Ti-2CNT) was prepared by milling in a planetary ball mill under H2. Activation of the sample was not required. At the first cycle, the sample absorbed 3.75 wt% H for 10 min, and 4.17 wt% H for 60 min at 593 K under 12 bar H2. Reactive mechanical grinding of Mg with Ni, NaAlH4, Ti, and CNT is thought to create defects on the surface and in the interior of Mg, as well as to reduce Mg particle size.