The synergy of high strength and ductility is crucial for industrial applications. Grain refinement strengthening is a well-known method for strength improvement. However, it leads to poor ductility due to plastic strain instability in the early stage of deformation. Recently developed novel heterogeneous microstructure designed materials called “Harmonic Structure” (HS) can overcome this strength-ductility trade-off. HS designed materials consist of grain size gradient wherein fine grains (‘Shell’) form a connected network surrounding coarse grains (‘Core’). The HS materials exhibit an outstanding combination of strength and ductility that is associated with high strain hardening due to suppressing local deformation. However, the conventional mechanical milling (MM) process for fabricating HS designed materials is time-consuming. Therefore, in the present study, a novel Bi-modal Milling (BiM) process is proposed to achieve HS designed materials more efficiently in a shorter time. The HS design has been applied to SUS316L powder via conventional MM and novel BiM process. Both the HS compacts exhibited approximately similar mechanical properties. Therefore, the proposed BiM technique is more appropriate for the industrial production of HS designed materials.