- “Do you want a "hey girl" or "what up girlfriend"?”— Katie ("Our Intern Class")
Dr. Katie Collins is an intern at Sacred Heart Hospital.
Katie seems very outwardly nice to people, but Sunny states in her video diary that she thinks that Katie would "gladly stab you in the back". (Our Intern Class) She wants to be right all the time, even to the extent of sabotaging the answers of her fellow interns. ("My Jerks") She is a suck up, and is not trying to hide it. After a discussion with Carla, Katie allowed herself to be more vulnerable to people's opinions and to ask for help. ("My Saving Grace") Katie tries to talk to patients to work through problems before trying other methods of getting them to cooperate, but has had some bad experience with this method, as once a homeless man spit on her face when she tried to get him to stop chewing on his stitches. ("My Full Moon")
When Katie was 6 years old, her father died. To cope, her mother turned to alcohol. Katie believes she has had to do or get anything she wanted by herself, no matter what it took. At Sacred Heart, however, Carla informed her that she isn't the only one with family issues, and that the hospital staff will be her new loving family if she is more down to earth. ("My Saving Grace") However, Katie does not change and cons Elliot into convincing Turk to give her a research opportunity (however this episode was originally intended to be broadcast ahead of My Saving Grace). ("My ABC's") A couple of days later, J.D. and Turk use Katie as a messenger between the two of them. ("My New Role")
- Blair (from The Facts of Life) (Turk) (J.D.) ("My Jerks")
- Mini Elliot (Keith) ("My Jerks")
- The Suck Up (Denise) ("My Jerks")
- Legally Blonde (Dr. Cox) ("My ABC's")
- Skank (Elliot) ("My ABC's")
- Katie's last name is revealed in "My ABC's".
- At the end credits of "Their Story II" she is credited as Katie Cummings. It's unknown, if this or her signature in "My ABC's" is her real full name. This, however, is only true for the version, that aired on March 25th 2009 on ABC, on later reruns and on The Complete Eighth Season DVD and Blu-ray she is credited as Katie without a second name.
- Katie was a L.U.G. (Lesbian Until Graduation) her last semester of medical school. (The Late Night with Jimmy Show)
- Katie says she will give anyone the side-boob. On "Their Story II" both Howie and Denise get the side-boob.