Zach Braff is the center of the show. His character, Dr. J.D. Dorian, has a continuing monologue tying the events of the program together. As the show continued, every once in awhile there is another narrator, but this is usually J.D.'s job. His best friend, Dr. Christopher Turk, is played by Donald Faison. Turk and J.D. work through their troubles at the hospital together by remembering their more childish moments and often times reliving them. The show works to showcase how all problems, no matter how complex, usually come down to base human emotions you have understood since childhood.
Sarah Chalke plays Dr. Elliot Reid. A quirky, clumsy girl, she is given a hard time for being a female doctor by her superiors. She and J.D. are often on a collision course to romance and have a brief coupling half way through the series. The rest of the series deals with the fallout as they move on to date other people. Nurse Carla Espinosa is played by Judy Reyes. This nurse knows more than many of the doctors and gets bitter about the new interns being her boss. This spicy attitude leads to a romance and eventual marriage with Christopher Turk.
The hospital would not be complete without those who give the interns a difficult time on their quest to become full-fledged doctors. Dr. Perry Cox singles out J.D. for constant ridicule and is played by John C. McGinley. Giving Dr. Cox a hard time is the head of the hospital, Dr. Bob Kelso, portrayed by Ken Jenkins. Neil Flynn plays the janitor who hates the interns and sets booby traps for them whenever he can. Finally, there is Sam Lloyd who plays Ted Buckland, the sidekick and whipping boy of Dr. Kelso.
There are only two regular, supporting females in the cast. Nurse Laverne Roberts is played by Aloma Wright. An older nurse, she not only gives the doctors a hard time but also consistently singles out Carla. She seems to only respond to Carla's husband Turk when it comes to any type of request. Jordan Sullivan, played by Christa Miller, is Dr. Cox's wife. She is difficult and self-centered, leading to much trouble not only for her husband but his underlings.