<p>Metallic glass composites hold significant potential as structural materials. However, few methods are available to enhance their mechanical properties post-casting. In this study, simple pre-tensile training was applied to a TRIP-reinforced metallic glass composite, resulting in a more than one-third increase in plasticity, while the reliability of plasticity was also enhanced. The deformation mechanism was further elucidated, revealing that pre-tension induced the formation of multilayered nanostructures at the dendrite–glass interface. This microstructural evolution facilitates the formation of finer martensite laths within the dendrites and multiple shear bands in the glass matrix during compression, thereby enabling more uniform plastic deformation. These findings suggest that simple preloading treatments may offer a viable approach to regulating the microstructure of as-cast metallic glass composites and optimizing their mechanical properties.</p> Graphical abstract <p></p>