Abstract: This study investigates the impact of silver (Ag) substitution on the microstructure and hydrogen storage properties of an Mg2Ni-based alloy. Density functional theory (DFT) calculations as well as universal machine learning interatomic potentials are used to explore how Ag substitution leads to a decreased hydride desorption energy. Experimental analysis of arc-melted Mg1.95Ag0.05Ni alloys and melt-spun Mg1.95Ag0.05Ni ribbons reveals structural changes between the two different production methods. XRD, SEM, DTA, TGA, and TEM confirm refined microstructures. In addition, hydrogen properties of melt-spun ribbons were measured with Sievert type and electrochemical device. The Sieverts-type measurement demonstrates about 3 wt.% H2 absorption and desorption, while electrochemical measurements show an initial discharge capacity of 80 mAh/g, with gradual fading over cycles. XPS unambiguously confirms Ag substitution and provides detailed insight into surface oxidation processes induced by prolonged exposure to ambient conditions. The results demonstrate that Ag incorporation plays a key role in tailoring the microstructure and significantly enhancing the hydrogen storage performance.