In the fourth season, the laughs are off the charts in TV's most surreal and sidesplitting show. Matthew Perry, Tom Cavanagh and Molly Shannon are just a few of the guest stars joining the staff in Season 4.
The new Dr. Clock arrives with her spaced out personality and doesn't cease to call J.D. "Johnny". But J.D. is fine with it, because there is nothing that is going to bring down his last week of being a resident before he officially becomes a full fledged doctor.
Dr. Clock tries to reconcile J.D. and Elliott, while waiting to see which one Dr. Cox will give the Chief Resident position.
Janitor has mad it his new mission to get everyone to call J.D. "Co-Chief Resident" and Elliot "Chief Resident" even though they are truly equal in status. Meanwhile Turk is angry because The Todd is having a great streak in surgery and J.D. doubts Turks skills because one of his patients dies. At the same time Dr. Cox and Jordan’s relationship is going great, when Ted brings them news that somehow his divorce papers and Dr. Cox's got mixed up and the technically never divorce.
J.D. is shocked to hear Dr. Cox (who he has called in for a pep talk) tell his interns that eventually, they will screw up and kill a patient.
Elliot becomes unsure she wants Molly as her mentor when she finds out that Molly doesn't have a perfect home life. J.D. is tested in leadership skills when Dr. Cox yells at him in front of his interns.
When Dan resurfaces, J.D. is shocked to learn his father has passed away.
When J.D. finds Dan with Elliot, Turk tells him to use the hurt brother excuse to get them to break up, just like Turk uses his diabetes to get stuff from Carla. But then J.D. realizes he wasn't hurt at all... Dr. Cox and Dr. Kelso unite to try and torment their common enemy -- Dr. Clock.
When Molly takes a job in another city, she and J.D. end up having a night of kissing and he tries to rush to sleep with her before she leaves.
J.D. is approached by a malpractice attorney, asking him to do a risky procedure on her father. Meanwhile, Elliot guides Doug to a new career path and Turk struggles to avoid a hypochondriac patient.
With the case against Turk on his mind, J.D. attempts to end it with Neena, but she won't take no for an answer and keeps him wrapped around her finger until J.D. summons Jordan to get involved.
J.D. takes matters into his own hands, when searching for a relative for his favorite patient. Meanwhile, Elliot is fed-up with co-workers not taking her seriously, and discovers she can get her way by flaunting her femininity with some help from Carla and Jordan.
When J.D. must address a bunch of pre-med students about what it's like to be a doctor, he strays off the beaten path and chooses to discuss his best moments as a doctor instead.
J.D. and Elliot are finally again getting along as friends and work partners, but the balance is upset when Elliot starts showing J.D. up as the calmer, more competent doctor, thus allowing her to teach him a few things.
A man is brought into the hospital after a bar fight by a man named Billy (Collin Farrel). Carla tells J.D. and Turk that it is the mans brother. Meanwhile Elliot and Carla continue to make plans to hang out with each other that they do not keep. Also Dr. Cox gets a vasectomy with out telling Jordan.
J.D. falls for a bartender at a club who mentions she has been looking for a doctor. J.D. later finds out she needed a doctor for her boyfriend, a big time college basketball player. At the same time Elliot decides to stand up against Dr. Kelso who believes her malaria patient is as good as dead. Meanwhile Dr. Cox is forced to record a big basketball game he will have to miss and declares war against anyone who tells him the final score.
J.D. struggles to impress Kylie on their first date; during a hospital quarantine, Turk learns that Carla once dated Cox; Danni Sullivan returns to annoy everyone; Laverne, Kelso, and Janitor fight over a "face cake."
When J.D. meets a former writer from his all-time favorite TV show "Cheers," JD begins to picture his life at the hospital as a bland, multiple-camera sitcom where everything is perfect and wraps up nicely.
J.D. is thrown out of the apartment; Turk and Carla continue to struggle to keep the romance alive; Cox has reason to believe that the son of an old buddy is autistic.
J.D. ditches a seemingly uninterested Kylie for Dr. Clock, who just returned from Milwaukee; Carla fumes over Turk's frequent phone calls to an ex-girlfriend; Janitor and Cox make a wager over Elliott.
Kelso dons SCR to prove a point to Cox, only to watch it backfire when an obnoxious patient refuses to listen to him; J.D. and Turk party while Carla struggles to find solace in Elliott.
When Carla and J.D. go out to let Carla have some fun, they get drunk and end up accidentally kissing.
J.D. and Carla get the silent treatment from Turk, who can't seem to control his emotions after learning about their kiss.
Turk won't open up at couple's therapy; Elliott refuses Cox's romantic advice when a very attractive man saunters into the hospital; J.D. learns a lesson in humanity from a dying old woman; Janitor accidentally lets a bunch of rats run around Sacred Heart.
Elliot is torn between moving too quickly and ruining her new relationship with Jake. Dr. Cox teaches Turk about having a healthy ego and Dr. Kelso and the Janitor fight over who gets to use the motorized cart.
With their residencies over, there are big changes at Sacred Heart. J.D. moves out to live on his own while Turk and Carla consider a family change.