Despite efforts to isolate industrially valuable Xe (xenon) and Kr (krypton), porous materials that satisfy high selectivity and uptake and the proper structural integrity in wet environments remain underdeveloped. We report an ultramicroporous metal–organic framework (MOF), Ni(AIN)₂ (HAIN = 3-aminoisonicotinic acid), which is favorable for the preferential adsorption of Xe. Notably, the amino groups form intra- and inter-net hydrogen bonds within the Ni(AIN)₂ structure, imparting structural stability even under wet conditions. Henry's selectivity and the Xe uptake at 0.2 bar were respectively 23.19 and 57.33 cm³ g⁻¹, falling into an ideal performance regime. Breakthrough experiments showed that under dry and humid conditions, the dynamic separation efficiency of Ni(AIN)₂ was maintained without any structural collapse. Thus, we provide a feasible design strategy for MOF adsorbents to achieve the desired Xe uptake, Xe/Kr selectivity, and structural stability.