|The Bold and the Beautiful|
|Portrayed by|| Nancy Sloan (1987–2004)
Heather Tom (2007–present)
|First appearance||March 23, 1987|
|Last appearance||Still on the show|
|Residence||Los Angeles, California|
- Nick: "How do you like it? Cream? Sugar?"
- Katie: "Uh, no, I like it unadorned."
- Nick: "Why am I not surprised? You seem like a lady who likes her coffee black. The stronger, the better."
- — Nick and Katie
Growing up, Katie was practically raised by Brooke, as their father had walked out on the family and their mother Beth struggled. Due to this, Katie and Brooke had a very close relationship for many years, which was later destroyed by Brooke's affair with Katie's husband Bill. Katie suffered from postpartum depression and stress as a result of motherhood and the worry brought on by her own husband.
Since her depression, Katie has taken Taylor Hayes on as her doctor, and remained on medication to avoid the depression coming back. Her marriage to Bill suffered when he had an affair with her sister Brooke. Katie caught the pair in many compromising positions, eventually leading to them having sex. This led to Katie giving Bill her rings and asking for a divorce.
- "What happened, Brooke?"
- —Katie asking her sister
Despite her jealousy and insecurities, Katie remained close to her sisters. Donna coerced her friend, Rocco, to date Katie. Eventually, Katie developed feelings for Rocco who in turn kissed and loved Donna.
Even after this, Katie continued dating Rocco. She ended it when she discovered he wanted to propose to Donna. She then developed a crush on someone named Kurt. Against Storm and Brooke's wishes, Donna and Katie tracked down their father, who had left the family years before. He reunited with Beth, their mother, and the family moved to Paris. Katie was the babysitter of Brooke's children.
Katie did not return to Los Angeles until 2007. When she did, the character's portrayer was changed from Nancy Sloan to Heather Tom.
Ruining her sister's wedding
Upon her return to Los Angeles in 2007, Katie