Metallic alloys produced by laser powder bed fusion (LPB-LB/M) metal additive manufacturing (AM) are often characterized by out-of-equilibrium heterogenous microstructures due to the process-related complex thermal cycles induced by highly localized melting, layer-wise fabrication, strong temperature gradients, and repetitive melting-solidification and heating-cooling cycles. The process-induced microstructure heterogeneities (e.g. heterogeneous grain structure, elemental segregation, and dislocation networks) are ranging from macro to nano scale and can greatly influence the mechancial behavior and properties of materials. Multi-principal element alloys such as high entropy alloys (HEAs) are currently gaining significant interest owing to their wide compositional space offering a great potential to outperform conventional alloys in various applications. For hydrogen-related applications, materials with a high resistance to hydrogen-induced degradation are highly required. In this study, we investigate the influence of microstructural heterogeneities induced by LPB-LB/M process on the hydrogen-metal interactions in Fe40Co25Ni25Al10 alloy. The metallographic investigations of the as-built state revealed the presence of the elemental segregation in cell-structure arrangements at sub-micron scale. In these elemental segregation cell-structures dislocation networks are observed as well. The observed heterogeneities in the as-built state are not pertained in the annealed state (1250°C for 6 hours). The susceptibility of the investigated alloy to hydrogen embrittlement has been evaluated by means of slow strain rate tensile (SSRT) tests with and without ex-situ electrochemical hydrogen charging. The amount of hydrogen in each alloy condition has been quantified by means of thermal desorption spectroscopy (TDS) up to 900 °C and correlated to the corresponding resulting macro mechanical properties from SSRT tests. Moreover, nano-indentation tests have been utilized to explore the interplay among the AM-induce microstructural heterogeneities, hydrogen and micro and sub-microscale properties. It turns out that the microstructure heterogeneities induced by AM process have a positive effect on the hydrogen resistance. This study demonstrates that sub-micro structures and heterogeneities such as elemental segregation cell-structures and dislocation networks in AM-alloys can be utilized to alleviate the known negative influence of hydrogen on mechanical behavior of metallic alloys.