The present invention is directed to a coordinating catalyst system comprising at least one bidentate or tridentate ligand containing pre-catalyst transition metal compound, (e.g., 2,6-bis (2,4,6-trimethylarylamino)pyridyl iron dichloride), at least one support-activator (e.g., spray dried silica/clay agglomerate), and optionally at least one organometallic compound (e.g., triisobutyl aluminum), in controlled amounts, and methods for preparing the same. The resulting catalyst system exhibits enhanced activity for polymerizing olefins and yields polymer having very good morphology.