The present disclosure provides engineered ketoreductase enzymes having improved properties as compared to a naturally occurring wild-type ketoreductase enzyme. Also provided are polynucleotides encoding the engineered ketoreductase enzymes, host cells capable of expressing the engineered ketoreductase enzymes, and methods of using the engineered ketoreductase enzymes to synthesize a variety of chiral compounds. The engineered ketoreductase polypeptides are optimized for catalyzing the conversion of N,N-dimethyl-3-keto-3-(2-thienyl)-1-ketopropanamine to (S)--N,N-dimethyl-3-hydroxy-3-(2-thienyl)-1-propanamine.