We show here that cerium and gallium‐doped dysprosium iron garnet (Ce,Ga:DylG) sputtered films may have widely varying magnetic properties that are functions of the predeposition sputtering system base pressure. A Ga site preference model that qualitatively accounts for these differences is introduced and is seen to agree with previously reported experimental results on the Ga site distribution and kinetics in liquid phase epitaxial and flux grown garnet films. Furthermore, we show strong evidence that indicates that the large Faraday rotation in highly doped Ce‐substituted sputtered garnet films is not solely ascribable to Ce+3intraorbital transitions as has been suggested for low concentration Ce:YIG. On the contrary, it is seen that the Faraday rotation in our materials increases almost exclusively in the near‐infrared region as the Ce+4/Ce+3ratio increases. It appears that this effect is largely due to an enhanced tetrahedral sublattice contribution to the Faraday rotation.