Abstract: Ti-Mn-based hydrogen storage alloys have attracted considerable attention for clean energy storage and hydrogen utilization because of their relatively low cost, moderate plateau pressure, and favorable hydrogen absorption/desorption kinetics. However, their practical application is still limited by poor resistance to oxygen poisoning, rapid degradation of effective hydrogen storage capacity, and stringent regeneration requirements after exposure to air or oxygen-containing atmospheres. In this work, Ti_1.25Mn_1.75-xCr_x + 3 wt.% Ce (x = 0, 0.25, 0.5, and 0.75) alloys were systematically investigated to clarify the effect of Cr substitution for Mn on the microstructure, hydrogen storage performance, oxygen poisoning behavior, and low-temperature regeneration capability. The results show that all the alloys are predominantly composed of the C14 Laves phase, while Ce mainly exists as an oxide secondary phase. With an appropriate amount of Cr substitution, the hydrogen storage performance is notably improved. Among the investigated compositions, the Cr25 (x = 0.25) alloy exhibits the best overall performance, reaching a maximum hydrogen absorption capacity of 1.51 wt.% at 298 K. The improved hydrogenation behavior is closely related to the optimized phase composition and the modified surface chemistry brought about by Cr incorporation. After oxygen poisoning treatment, the effective hydrogen storage capacity of all samples decreases markedly, confirming that surface oxidation severely suppresses hydrogen activation and uptake. Nevertheless, the Cr25 alloy still retains the highest post-poisoning effective hydrogen storage capacity and capacity retention ratio among the tested alloys, indicating superior tolerance to oxygen exposure. X-ray photoelectron spectroscopy (XPS) analysis indicates that Cr and Ce are more readily oxidized on the alloy surface, and thus act as sacrificial elements that preferentially react with oxygen. This behavior helps delay the oxidation of the main alloy phase and preserves surface activity to a certain extent. In addition, the poisoned alloys can be effectively regenerated at 318 K, which is a relatively mild temperature compared with many conventional regeneration processes. After the first regeneration cycle, the effective hydrogen storage capacity of the Cr25 alloy recovers to 1.38 wt.%, corresponding to a regeneration rate of 93.2%. Such low-temperature recovery performance is highly desirable for practical operation, thereby reducing the energy input required for reactivation after air exposure and improving the feasibility of repeated use in real applications. Overall, this study demonstrates that Cr substitution is an effective strategy to simultaneously enhance the hydrogen storage performance, oxygen poisoning resistance, and low-temperature regeneration ability of Ti-Mn-Ce alloys. These findings provide useful insights for the design of durable hydrogen storage materials with improved environmental adaptability, operational reliability, and application potential in clean energy systems.