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

Dr. Cox: Pumpkin, that's modern medicine. Advances that keep people alive that should have died along time ago, back when they lost what made them people. Now your job is to stay sane enough so that when someone does come in that you actually can help, you're not so brain dead that you can't function-for the love of God, what?
J.D.: Its just... do you think we should be talking about this in front of her?
Dr. Cox: Her? She's dead. Write this down newbie, if you push around a stiff, nobody will ask you to do anything.
J.D.: You've been like a father to me.
Dr. Cox: Fair enough, you want some real advice? If they find out they nurses are doing your proceedures for you, your ass will be kicked out of here so fast it will make your head spin

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?"

Scrubs Quotes

Dr. Cox: Pumpkin, that's modern medicine. Advances that keep people alive that should have died along time ago, back when they lost what made them people. Now your job is to stay sane enough so that when someone does come in that you actually can help, you're not so brain dead that you can't function-for the love of God, what?
J.D.: Its just... do you think we should be talking about this in front of her?
Dr. Cox: Her? She's dead. Write this down newbie, if you push around a stiff, nobody will ask you to do anything.
J.D.: You've been like a father to me.
Dr. Cox: Fair enough, you want some real advice? If they find out they nurses are doing your proceedures for you, your ass will be kicked out of here so fast it will make your head spin

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?"