A novel (8.5Al3BC + 14.5Al2O3)/Al composite was fabricated with exceptional elevated-temperature properties and stiffness. The composite boasts an average Young’s modulus of 99 GPa, with ultimate tensile strength and elongation of the composite at 350°C averaging 188 MPa and 4.4%, respectively. The synergistic strengthening effect of Al3BC and γ-Al2O3 is responsible for the high-temperature properties, while they both contribute to the improvement of stiffness as they have a high initial Young’s modulus. This innovative composite design holds promising potential for advancements in material engineering and performance optimization.