Katherine Irma Mayfair is a fictional character created by Marc Cherry for the ABC television series Desperate Housewives. The character was portrayed by Dana Delany and first appeared in the series' fourth season premiere on September 30, 2007, as the focus of the yearly mystery. Delany's portrayal received praise from critics and audiences, with many critics attributing the improved quality of the series' fourth season to Delany's performance. The actress was a critics' favorite for a Primetime Emmy Award nomination for Outstanding Supporting Actress in a Comedy Series in 2008.