This study investigates the influence of varying rolling reduction on the evolution of microstructure and mechanical properties of Mg10Gd (in wt%) alloys by caliber rolling (CR). By increasing the rolling reduction from 45 % to 65 %, a uniform bimodal structure is obtained in which coarse grains (CGs) larger than 10 µm are surrounded by fine grains (FGs). The MgGd alloy subjected to 65 % reduction exhibits superior mechanical properties, i.e. yield strength (YS) of ~424 MPa, ultimate tensile strength (UTS) of ~500 MPa and elongation (El.) of ~3.3 %. The synergistic improvement in strength and ductility is primarily attributed to the combined effects of low-angle grain boundary (LAGB) strengthening, precipitation strengthening, and the coordinated deformation exhibited by the bimodal structure. In addition, caliber rolling also provides a novel approach for the design of Mg alloys with uniform bimodal structures that exhibit both high strength and ductility.