- “Everyone's got their own burdens, J.D., and I'm not gonna be one of those people that dumps mine on somebody else.”— Dr. Kevin Casey
Dr. Kevin Casey was a talented doctor and surgeon that worked as a visiting doctor at Sacred Heart Hospital temporarily. He suffers from obsessive-compulsive disorder.
Casey and Dr. Cox were residents at the same hospital when they were younger. Casey had to drop out because of the severity of his obsessive-compulsive disorder. He says that he read his medical books and journals over and over again, explaining why he is so good at giving instant diagnosis. ("My Catalyst")
He makes a grand entrance at Sacred Heart, and whilst he initially appears to be the "mentor" that J.D. always wanted, he upsets him whilst the two are at the bar having a beer by saying that it is wrong to need a mentor after being in medicine for so long. After he beats Turk's record time at a surgery, Turk is unhappy with his appearance at the hospital. Dr. Cox also gets annoyed by Casey when he appears to be better at giving instant diagnosis of patients, and even manages to discover why Carla's food tastes unusual.
After J.D's attempt to confront him and lash out at him, J.D. realizes that what made Dr. Casey a masterful professional was not a gift, but rather a curse. The three realize that all of their problems aren't as important as what Dr. Casey has to deal with because of his OCD, they decide that he does not deserve their hate. J.D. uncomfortably stands by as Casey is unable to stop washing his hands two hours after a surgery is over. When Casey gets angry at himself because of his condition, J.D. begins to comprehend and realizes the hardship he has to suffer with his curse everyday. ("My Catalyst")
Later, the Janitor installs a toilet on the roof, claiming that he can look at his life better than if he used a "germ-infested" stall in the building. He names it his Epiphany Toilet, and Casey finds himself unable to use it, saying that it is "his Everest". In the hospital Elliot is unhappy that Casey has apparently given help to everyone else there, but not to her. She asks him for some help with a simple procedure that she is now, for some reason, unable to do. By showing her that he could finally bring himself to use the toilet on the roof, conquering a great fear, she understands that she can do the procedure, and helps her to overcome her fear.
- Whenever Dr. Casey enters or exits a building, He must go in and out three times. He does this upon entering the hospital on his debut, and then leaving Sacred Heart. When he makes an entrance in a building he needs to step in with his left foot first, and exhale simultaneously as his right foot plants.
- According to Dr. Casey, whenever he goes to the bathroom, the process involves going home and scrubbing down his home toilet with industrial strength cleaner for an hour.
- He insists on being called Dr. Kevin Casey or just Kevin when addressing him.
- When he signs something, he must do it several times and utter his name as he signs it.
- Each day at work, he must touch every object (and person) in his first patient's room and say "Bink" repeatedly.
- Dr. Casey must put a new coaster on the top of a bottle after every time he takes a sip from it.
- The name Kevin Casey is similar to Ken Kesey, a famous American author. His biggest novel, "One Flew Over the Cuckoo's Nest", is set in a psychiatric ward in which one of the characters, George Sorensen, has severe obsessive-compulsive disorder.
- Bill Lawrence created Kevin Casey with OCD to cover up Michael J. Fox's Parkinson's disease.