This study reports the synthesis of a high-entropy AlFeCuTiNi alloy via high-energy ball milling. The study investigates the effects of mechanical alloying time and sintering temperature on the microstructure, mechanical properties, wear, and corrosion behavior of the high-entropy AlFeCuTiNi alloy. XRD, SEM, and EDX analyses revealed that the mechanical alloying time and sintering temperature significantly affected the alloy’s homogeneity, phase structure, and oxide film stability. As the mechanical alloying time increases, the corrosion resistance of alloys sintered at 550 °C initially increases and then stabilizes. In samples sintered at 650 °C, corrosion resistance is generally higher. The highest corrosion resistance was achieved after 15 h of mechanical alloying and sintering at 650 °C. The study reveals that the best corrosion, wear, hardness, and wear density performance was observed in samples obtained at medium conditions, achieved after 20 h of mechanical alloying and sintering at 650 °C. These findings may contribute to optimizing production processes for sustainable material design. Moreover, this research highlights that high-entropy alloys and powder-metallurgy-based production methods enable industrial applications for energy-efficient, sustainable material design and contribute to sustainable production and circular-economy principles.