Kitty is the third oldest child and second daughter of William and Nora Walker. In the beginning of the series, Kitty has just returned back to Los Angeles after living in New York City for years. While in NYC, Kitty was a radio host. Kitty is a staunch Republican, just as her father was. Kitty often butts heads with her liberal mother, Nora on various occasions.

Kitty is in a relationship with Jonathan, a hedge fund manager when the series starts and later sleeps with co-star, Warren. They later begin a relationship but when he fails to end his relationship with intern, Amber, Kitty ends it, knowing Amber really cares for Warren. At the end of season 1, Kitty begins dating Senator Robert McCallister. She is also his communications director. In season 2 as Robert is running for President, Kitty finds out she is pregnant with Robert's child. She is reluctant to tell Robert due to the fact that she knows how this will affect the campaign. Soon after Robert finds out, Kitty goes to a doctors appointment and finds out that she has had a miscarriage. Kitty and Robert then both agree that they don't want to wait any longer to get married. So after a whirlwind romance, Kitty marries Robert.

Kitty also is the one who married her brother Kevin to Scotty.

Months after Kitty and Robert endure a miscarriage, they decide to have a child. Without much luck, Kitty decides to try fertility treatments. After all of the treatments prove to be unsuccessful, both Kitty and Robert mutually agree that they should adopt a child.