Doctor Jonathan Micheael "J.D." Dorian is the main character and narrator of Scrubs and is played by Zach Braff.  J.D. is best friends with Turk, who he's been friends with since they were roommates in college.  J.D. quickly meets Elliot, who he falls for hard and has an on and off again relationship with throughout the series. 

J.D.'s mentor is Dr. Cox who he is constantly trying to impress without making much headway.  He also has a bitter rival at Sacred Heart who torments him endlessly... The Janitor.  J.D. frequently daydreams where he tilts his head to the side and drifts away.

J.D. Quotes

J.D.: My man Turk, is getting it daily and nightly and ever so rightly! Ah! What up, dogg!
J.D.'s narration: Once every 4.2 seconds a man says something stupid that a woman hears and punishes him for... luckily, this wasn't one of those times.
Carla: What did you just say?
J.D.: "What up...dogg?"

J.D.: Does anyone know what the cause of death may have been?
Keith: Maybe when you leaned over to check his I.V., you smothered him to death with one your love handles.
J.D.: What did you say, Keith?
Keith: Dr. Reid told me if you picked on me I should stand up for myself. And that you're very sensitive about your doughy physique.

Scrubs Quotes

I'm narcissitic, I'm pessimistic, I'm obsessive, I'm insecure, and I am so afraid of intimacy that every one of my relationships is a journey of self sabatoge that inevitably end in a black vacuum of shattered expectations and despair.

J.D.

Doug wanted me to give this patient five hundred thousand milligrams of morphine. I thought I'd check with you before I kill a man.

Laverne