Based on thermodynamic calculations, a novel Sc- and Zr-microalloyed Al-Ce alloy was designed, and Al-10 wt.% Ce-0.3 wt.% Sc-0.25 wt.% Zr was selected as the target composition. The alloy was fabricated using laser powder bed fusion (LPBF). Combined with the isothermal age-hardening curve at 300 ℃,the microstructures and room-temperature tensile properties of the as-built alloy and the sample aged at 300 ℃ for 1 h were analysed. After aging at 300 ℃ for 1 h, a hierarchical microstructure consisting of microscale Al11Ce3 eutectic phases, nanoscale L12-Al3 (Sc, Zr) precipitates, and nanoscale stacking faults is formed in the alloy. Compared with the as-built state, the yield strength increases from (334.2± 5.3) MPa to (391.3±6.1) MPa, and the ultimate tensile strength increases from (463.8±1.6) MPa to (552.9±6.5) MPa after aging for 1 h, without causing an obvious loss of ductility. The strength enhancement is attributed mainly to the effective impediment of dislocation motion by L12-Al3 (Sc, Zr) precipitates and stacking fault structures, whereas the retention of ductility is associated with local stress relaxation and improved deformation compatibility induced by microstructural recovery during aging.