Strong, ductile, and irradiation tolerant structural materials are in urgent demand for improving the safety and efficiency of advanced nuclear reactor. Amorphous ceramics could be very promising candidates for high radiation tolerance since they do not contain conventional crystal defects that are induced in crystalline materials under irradiation. However, amorphous ceramics exhibit ‘brittle-like’ behavior. We realized the strength-ductility-irradiation tolerance combination of amorphous ceramic composites (ACCs) through tailoring nanosized heterogeneities. Principles for the design of such ACCs are that metal elements should prefer to form nanosized metal-rich clusters in ACCs. Moreover, the phase structure and properties of the heterogeneity can be modified by synthesis and annealing conditions. By averting plastic flow localization and enhancing irradiation tolerance, we impart to ACCs the ability to undergo both uniform plastic deformation and irradiation tolerance, markedly advancing their potential for use in nuclear industry as core structural materials.