Non-equiatomic FeNiCoAlTaB high-entropy alloys (NCATBs) exhibit promising engineering application potential due to their unique elemental composition. However, the element segregation and NiAl phase alone at the grain boundary generated by traditional processing techniques can compromise the strength properties of the material. On this basis, a non-equiatomic FeNiCoAlTaB high-entropy alloy (NCATB-HEA) with a balance of strength and ductility was fabricated via laser powder bed fusion (LPBF), followed by a 600 ℃ low-temperature aging treatment. The effects of processing parameters on the densification, microstructure, residual stress, and mechanical properties of the alloy were systematically investigated. The results show that a proper combination of laser power and scan speed significantly reduces the number of defects and improves the density. Rapid solidification introduces a high density of dislocations and refines the grain structure with an evident texture. Heat treatment promotes the formation of γ′ and B2 precipitates, which synergistically evolve with grain boundaries to increase the alloy strength. This work demonstrates that the integration of additive manufacturing and heat treatment enables the coordinated strengthening and toughening of NCATB alloys, offering promising mechanical performance and engineering potential.