Using yttrium aluminum garnet (YAG) crystallites as seeds, highly dispersed and isometric nanocrystals of Ce-doped yttrium iron garnet (Y_3−xCe_xFe₅O₁₂, Ce-YIG) have been synthesized via a glycothermal process with the average size controllable through varying the concentrations of the relevant reaction species and YAG seed contents. The phase compositions, microstructures and magnetic properties of the as-synthesized Ce-YIG nanocrystals were characterized by XRD, FESEM, TEM, XPS and VSM. It has been found that the Ce-doping content x can reach as high as 1.7 with all Ce ions in the Ce-YIG nanocrystals being of a chemical valence +3. Moreover, the Ce-doped nanocrystals grown epitaxially on YAG seeds are characterized with a perfectly coherent lattice structure and possess much higher room temperature saturation magnetizations than that of the bulk YIG due to the Ce-enhanced super-exchange actions between Fe³⁺ ions, which is expected to greatly favor the enhancement of the off-resonance Faraday rotation.