<p>Eutectic high-entropy alloys (EHEAs) possess distinctive advantages derived from their multi-principal-element compositions coupled with regular lamellar microstructures. However, the random solidification microstructure and inhomogeneous phase distribution inherent to conventional casting processes severely constrain the synergistic enhancement of their strength and ductility. In this study, the Al₁₉Fe₂₀Co₂₀Ni₄₁ EHEA was selected, and directional solidification (DS) was employed to achieve precise microstructural control, constructing a multi-level lamellar architecture featuring a herringbone-like alternating arrangement. This tailored microstructure not only significantly refines the interlamellar spacing and eliminates detrimental isolated B2 phases, but also substantially promotes slip continuity of dislocations at the interfaces, thereby promoting the coordinated motion and uniform distribution of dislocations across multiple slip systems. Consequently, the EHEA exhibits superior mechanical properties compared to the most reported thermomechanical processed and directionally solidified HEAs. Further micro-mechanistic analysis reveals that the homogenized distribution of geometrically necessary dislocation (GND) density, the interfaces and multi-slip bands assisted crack deflection, and the multi-stage strain-hardening behavior induced by sequential activation of dislocations collectively contribute to its outstanding strength-ductility synergy. This work demonstrates that by programming the solidification path of a selected EHEA composition, it is feasible to design and fabricate a unique multi-level lamellar architecture. This spatially ordered microstructure serves as an intrinsic microstructural composite material, which fundamentally optimizes dislocation management and crack propagation, thereby providing a novel microstructural design paradigm for developing ultra-robust EHEAs for extreme service environments.</p>