The impact of Fe content on the microstructures and mechanical properties of an ultra-high strength aluminum alloy, namely, Al−10.50Zn−2.35Mg−1.25Cu−0.12Cr−0.1Mn−0.1Zr−0.1Ti, was investigated. It is found that the increase of Fe content leads to a notable rise in the volume fraction of microscale secondary phases, including (Cu,Fe,Mn,Cr)Al₇, σ phase (composed of Al, Zn, Mg, and Cu elements), and Al₃(Zr,Ti). The formation of these secondary phases results in the depletion of certain phase-forming elements, thereby significantly reducing the quantity of strengthening phases. Fe imposes minimal impact on tensile strength, but it can significantly alter the elongation (δ). For instance, the average elongation of the alloy with 0.18 wt.% Fe (δ=4.5%) is less than half that of the alloy with Fe less than 0.1 wt.% (δ=9.9%−10.9%). The reduction in elongation is attributed to the combined effects of the formation of coarse secondary phases and the diminished quantity of strengthening phases around these coarse phases.