Season 4 of Chicago Med premiered on September 26, 2018.
- Brian Tee as Dr. Ethan Choi
- Colin Donnell as Dr. Connor Rhodes
- Marlyne Barrett as Maggie Lockwood
- Nick Gehlfuss as Dr. Will Halstead
- Norma Kuhling as Dr. Ava Bekker
- Oliver Platt as Dr. Daniel Charles
- Rachel DiPillo as Dr. Sarah Reese (Episode One Only)
- S. Epatha Merkerson as Sharon Goodwin
- Torrey DeVitto as Dr. Natalie Manning
- Yaya DaCosta as Nurse April Sexton
|Be My Better Half||Diane Frolov & Andrew Schneider||Michael Waxman||September 26, 2018||#4x01|
|Goodwin finds herself quickly clashing with the new hospital COO Gwen Garrett while April questions whether or not Ethan's sister, Emily, is using again. Dr. Charles deals with his past actions.
|When To Let Go||Diane Frolov, Andrew Schneider & Danny Weiss||Charles S. Carroll||October 3, 2018||#4x02|
|In the second part of the three-show, one-night crossover event, the doctors and nurses of Chicago Med find themselves on high alert when an overflow of patients are rushed into the doors following a terrifying apartment complex blaze. Dr. Rhodes fights to save the life of one of "Chicago Fire's" own, while Dr. Halstead and his brother Jay struggle with their own personal battle.
|Heavy Is The Head||Jeff Drayer||Michael Waxman||October 10, 2018||#4x03|
|When a sick boy is brought in, Ethan is faced with a tough decision that quickly escalates into a complicated and dangerous situation. Connor and Maggie are put to the test, while Natalie and Ethan aren't sure what to make of Elsa, the new third year medical student
|Backed Against The Wall||Eli Talbert||Vincent Misiano||October 17, 2018||#4x04|
|Dr. Halstead gets an unplanned visit from the CPD while Ethan is skeptical of a woman who is experiencing chronic pain. Natalie tends to a cancer patient whose brother has strong feelings on why he is refusing to lend his assistance
|What You Don't Know||Stephen Hootstein||Donald Petrie||October 24, 2018||#4x05|
|When things become complicated, Will is forced to lie to Natalie. Ethan and April find out some compromising information about Emily's boyfriend and Ava is unsure of what to do with a patient who is refusing treatment.
|Lesser of Two Evils||Safura Fadavi & Meridith Friedman||Martha Mitchell||October 31, 2018||#4x06|
|Dr. Manning and Dr. Halstead become skeptical of a patient's injuries when the victim of a car accident is brought into the hospital. Ethan and April have a difficult time understanding Emily's attachment to her boyfriend despite recent developments. Will and Natalie brace for their joint bachelor/bachelorette party.
|The Poison Inside Us||Jeff Drayer & Joseph Sousa||Milena Govich||November 7, 2018||#4x07|
|The hospital is forced to evacuate when a toxic chemical is brought into the E.D., leaving patients and the staff in grave danger. Stuck in an elevator, Dr. Charles and Dr. Manning are forced to take drastic measures with a pregnant woman. Goodwin is tasked with making difficult choices and Dr. Rhodes discovers a secret that Dr. Bekker has been holding from him.
|Play By My Rules||November 14, 2018||#4x08|
|Dr. Charles struggles to convince Dr. Choi that surgery isn't always the answer. Dr. Rhodes finds himself in hot water with Goodwin when he disobeys her direct order. April becomes frustrated with Maggie when she continues to question her leadership role as the stand-in charge nurse. Dr. Manning suspects Dr. Halstead is keeping something from her.
|[[Image:|150px]]||Death Do Us Part||December 05, 2018||#4x09|
|Will and Natalie prepare for their big day, but an unsuspecting Will soon finds himself sidetracked. Dr. Charles disagrees with Goodwin on how to best handle a patient's treatment while Dr. Choi and April are on their own when a pregnant woman delivers. Dr. Rhodes finds himself operating on a patient that is of great importance to Det. Halstead.
Notes and Trivia
- The show was renewed for a fourth season by the NBC on May 10, 2018.
- Chicago Med was given a new timeslot: Wednesday at 8 P.M.
- On July 23, 2018 it was announced that Molly Bernard and Colby Lewis are set to recur during Season 4.
- The first promotional video was released on July 25, 2018, regarding the new "Chicago Wednesday'" timeslot.
- Every episode, so far, in Season 4 has a four word title.
- Rachel DiPillo leaving her role as Dr. Sarah Reese before the season airs.