There’s nothing wrong with an ego if you can back it up.
|― Morgan Reznick|
Dr. Morgan Reznick is an internist resident at St. Bonaventure Hospital. Morgan is revealed to be a former avid archer and to come from a family of famous artists that she is long-estranged from. Morgan has an arrogant and competitive personality that drives the other doctors crazy, but as time goes on she begins to lose some of this, particularly after Morgan makes a mistake that costs a patient her arm. Melendez subsequently compares Morgan's relationship with Shaun Murphy to that of himself and Dr. Lim during their own residency and suggests that their differing ways of approaching situations can be complimentary. In Season 3, she is diagnosed with rheumatoid arthritis which is starting to affect her hands. In Season 4, Morgan switches from surgery to being an internist, meaning she is studying internal medicine.
Morgan is from a famous family of artists with a mother who is a painter, a sister who is a composer and a brother who is a sculptor. Her mother, Caroline, was so consumed by her work that Morgan was left with a list of grievances growing up stretching back to the first day of preschool. Tired of her famous family overshadowing her, Morgan would often make up stories about her life that involved being an only child and her parents doing something else.
When Morgan was 5, she started learning archery and practiced every day for 7 years. She didn't stop until she left high school and went on to medical school where she decided that she needed to "grow up." In addition, she witnessed her mother suffer from rheumatoid arthritis which destroyed her hands and wrists. During her time in medical school, she mentored under Sonya Kung who was the surgical residency program at Denver Memorial Hospital. After graduating from medical school, Morgan got a job at San Jose St. Bonaventure Hospital as a surgical resident. She was given to the attending Dr. Matt Coyle along with fellow resident Alex Park.
After allegations regarding sexual harassment came to light about her attending Dr. Matt Coyle, he was transferred to another department and his residents on his service were distributed to other attendings. Both Morgan Reznick and Alex Park were transferred to the attending, Neil Melendez.
During "Quarantine" Morgan is revealed to be forming a romantic relationship with an EMT named Tyler. After Tyler falls ill from a deadly virus that quarantines the ER, Morgan works to treat him and is visibly devastated when he dies of the virus despite her best efforts. In "Quarantine: Part Two," Morgan treats Lim for the virus while determining that it is not airborne and that Tyler contracted it due to a ripped mask and bodily fluid contact. Thanks to Morgan's efforts and use of extracorporeal membrane oxygenation as a treatment, Lim survives. After quarantine ends, a devastated Morgan watches as the CDC takes away Tyler's body.
In "Aftermath," Morgan blackmails Claire into spending time with her, before admitting that she's still not over Tyler's death. After Claire's mother claims she is being evicted, Morgan accompanies Claire to help her and becomes convinced that Claire's mother is being abused. Revealing that she carries a gun, Morgan insists on confronting the man, only to learn that Claire's mom was having cold feet about an engagement. Afterwards, having learned that Morgan had a stalker in college, Claire realizes that Morgan is actually a battered woman and offers her support to Morgan if she ever needs it.
In "Disaster," after Lim announces that third-year residents can lead their own surgeries now, Morgan and Park compete over who will get to lead the surgery of an elderly man with treatable kidney cancer. A smug Morgan ultimately wins the competition. However, due to the man's dementia, Park advises his wife to leave the cancer untreated so that the man can enjoy the few years he has left with the cancer rather than lingering for years with the dementia. Park later requests Morgan's help in convincing the wife. Morgan, who is visibly affected by the case, speaks with the wife who has never lied to her husband on the matter, pointing out how hard the cancer fight will be with the dementia confusing him. The wife ultimately agrees to Morgan and Park's idea.
Throughout the episode, Morgan listens to Shaun's story of his date with Carly Lever and is disappointed when she learns that despite being eventful, it wasn't actually a disaster as Shaun claims. However, when Shaun explains how he was overwhelmed by the unpredictability he experienced, Morgan is sympathetic along with the rest of his friends. After the case is over, Morgan goes to visit her grandfather in a nursing home who is revealed to have dementia.
In "First Case, Second Base, she tells Dr. Glassman that she owns a Sig P365 gun.
In "Moonshot," Morgan is finally assigned her first lead surgery which pleases her as even though Morgan is the last to get it, it is an extremely complex surgery. Morgan has some troubles while practicing and approaches Andrews about giving her a simpler surgery. Andrews explains that he believes that Morgan has the potential to be a leader and he is setting her up to shine. Morgan later visits Dr. Glassman's clinic under false pretenses and eventually admits that she was diagnosed a month before with rheumatoid arthritis which her mother had suffered from. Morgan doesn't want to let Lim and Andrews know as it will change their opinions of her, but she knows how much Glassman believed in and fought for Shaun and asks him to do the same for her, insisting that she is only suffering from pain and not nerve damage yet. Glassman agrees and helps treat Morgan's condition so that she can perform the surgery which Morgan is successful in despite some initial hesitation. When she leaves for the night Glassman, rubs Morgan's knuckle which she doesn't appear to feel, suggesting that she is suffering from nerve damage afterall which Morgan brushes off. At home, Morgan submerges her hands in a bowl of ice to treat the pain she is in.
In "Incomplete," Morgan and Shaun treat Jeanie, a young woman with life-threatening tumors who would lose her ability to have sex if they are removed. Morgan advocates for Jeanie to have them removed anyway even though Jeanine and her fiancé Tony are hesitant. Morgan later confides in Tony that she once had a boyfriend she loved deeply and was perfect for her. However, a drunken one-night stand ruined Morgan's relationship, showing her that sex can make you stupid and isn't everything, its all the other parts of a relationship that are the most important. When Tony admits he isn't sure if he can have a relationship with Jeanie without sex, Morgan tells him to lie to get Jeanie to have the surgery and save her life which he does. Andrews later tells Morgan that though Tony may have been lying in the moment, deep down he was telling the truth and will eventually realize it.
At the same time, Morgan grows concerned as Shaun tries to have sex with Carly for the first time and then suddenly stops oversharing. Concerned about her friend, Morgan confronts Carly with her fears that Carly sees Shaun as a project and not a person and will break Shaun's heart. Carly shares a story of how Shaun went out of his way to help Carly as proof that she is going out with Shaun because he's a great guy who treats her well. Morgan seems to be pleased by this, but Carly tells Morgan that the condescending notion that someone needs an ulterior motive to be interested in Shaun means that its Morgan whose not seeing Shaun as a person. Morgan is left taken aback by this accusation.
In "Sex and Death," Morgan is shocked to be reunited with her long-estranged mother Caroline who had come to the hospital seeking a third opinion from Glassman regarding her cerebral cavernous malformations that will kill Caroline without a lobectomy. However, Caroline refuses as it could destroy her artistic ability. Morgan is shocked and upset, particularly as her mother and siblings never bothered to inform Morgan, the doctor of the family, of the problem. Morgan is against a procedure Shaun suggests that could cure the seizures her mother is having without treating the malformations, wanting to force her mother to accept help. However, she is talked down by a sympathetic Claire, using her own experiences with a mother that is different than she would like. Reunited with her brother Ariel, Morgan clashes with him several times over Caroline's treatment. She also takes the opportunity to outline her list of grievances against Caroline, but when she suffers a seizure, instantly rushes to comfort her mother, upset by her mother's situation despite their many differences.
Morgan eventually finds another solution that would save her mother without performing a lobectomy, but would require Glassman to do it. With Glassman reluctant to help, Morgan accuses him of being too afraid to learn that his own ability as a surgeon has been diminished by his cancer; though initially enraged, Glassman ultimately changes his mind and presents the idea to Caroline who refuses after Ariel won't back Morgan up. Park gets Morgan to see that she needs to stop competing with her brother and work together to save their mother. Morgan explains her plan to Ariel and gets him to lay it out for Caroline, knowing that her mother will listen to him. The surgery is a success and Caroline thanks Morgan for saving her life, but again pays her a backhanded compliment that upsets Morgan. Later, she and Claire listen as Lim helps Shaun understand sex by comparing the focus he will need to surgery; Claire and Morgan are left intrigued by the idea of all of Shaun's focus devoted to sex.
In "Hurt," Morgan, recovering from hand surgery, takes over the ER in the aftermath of an earthquake with everyone else too busy elsewhere. Morgan clashes with Nurse Deena Petringa over a patient that Deena suspects is pregnant which Morgan doubts; Deena performs an ultrasound anyway that apparently validates Morgan's beliefs. However, she quickly realizes that its an ectopic pregnancy which requires emergency surgery; with no surgeons or ORs available and the patient's life on the line, Morgan decides to perform the surgery herself.
In "I Love You," Morgan and Deena perform the surgery in the ER with Deena trying to get Morgan to limit her role due to her surgery; however, Morgan refuses as they can't afford to lose her with only Morgan and Deena there. The two succeed in saving their patient, but are interrupted by Andrews who accuses Morgan of trying to be a hero and kicks her out to finish the job himself. Andrews later examines Morgan's hands and admits that he was wrong in his opinion of Morgan as her actions proved that Morgan's patients are her first priority. However, doing the surgery may have damaged Morgan's hands to the point that her surgical career is ruined.
- As seen in "Aftermath," Morgan owns a gun and a concealed carry permit for it, stemming from when she had a stalker in college. However, Claire finds the idea of Morgan with a gun more scary then a potentially violent boyfriend. Morgan's proficiency with a gun was previously hinted at when she joined Park at the gun range to let off some steam.
- Morgan was infected with COVID-19 in "Frontline Part One" as confirmed in "Frontline Part Two." However, she recovered off-screen between the two episodes.
- Morgan built a potato gun for her 6th grade science fair and nearly got kicked out of school for it as a result as mentioned in "Newbies."