- "Well, in the future, I'll ask that you extend to me the same courtesy you would a crack addict."
- ―Jennifer Melfi, to Tony Soprano[src]
Jennifer Melfi is the psychiatrist of Mafia boss Tony Soprano.
Melfi is herself Italian-American; her family has roots in Caserta. She is a graduate of Tufts University. She received her Ph.D. from a correspondence school. She is probably the person closest to truly understanding Tony Soprano. Presumably educated in the Freudian school of psychoanalysis, Melfi doesn't rush to judgement when treating Tony and instead chooses to analyze his behavior, despite the fact that he appears to be an untreatable psychopath.
Over the years, Tony Soprano has been able to confide in Melfi many things that he has told no one else, not even his associates or his wife, Carmela. However, Melfi and Soprano have an unusual, on-again-off-again relationship. He inwardly fears Melfi prying into his life during their sessions, but he also fears the results from not dealing with the problem. As a result, she watches him go through frequent mood swings during their time together, sometimes acting playful, other times violent – sometimes acting responsive, other times being cold and distant. There are several occasions where Tony storms out of her office, either cursing at her or walking out in silence.
For her part, Melfi has tried hard to help Soprano as much as possible, half chalking it up to some sort of thrill of helping a gangster but also trying to resist the idea that she has romantic thoughts about the man— she wants to keep their relationship professional. Melfi, in addition, has an ongoing battle with alcoholism. While she resisted Soprano's constant advances, which have simultaneously attracted and appalled her, Soprano no longer wishes for their relationship to remain strictly professional, as he seems to see her as the one thing that he is unable to truly have and, while continuing to pursue her, also resents her for it.
From the conversations that Tony has with her about his mother, Melfi eventually suspects that Livia may suffer from Borderline Personality Disorder, and that it was her who tried to have her son killed; at first, Tony belittles her for this idea, but after discovering the truth (thanks to the FBI), soon apologizes and admits to Melfi that she was right about his mother. After this, she is advised to flee from Junior's wrath by Tony, who tells her "You've been a good doctor to me".
Melfi's son, Jason LaPenna, has a recurring role in her life as he is her only child. Jason's father is her ex-husband, Richard LaPenna.
During Season 3, Dr. Melfi is raped by a man in the parking garage of the building at which her office is located. The rape leaves her badly shaken and while the police do apprehend a suspect who is most likely the man who raped her, he is released on a technicality. Dr. Melfi and her ex-husband are furious about this, but there is nothing that they can do about it. Soon after, Dr. Melfi goes to a restaurant to have lunch and notices an Employee of the Month award on the wall. The employee pictured on the award is the very same man who raped her, and as Dr. Melfi realizes this, she leaves the restaurant. It is clear that Dr. Melfi is tempted to turn to Tony Soprano to punish the man, as the law failed to do so. She even dreams of the man being attacked by a vicious and large attack dog, a subtle reference to Tony. Tony still does not know that Dr. Melfi had been raped, as Dr. Melfi had given another reason as to why she had been absent from their sessions. When she returns and meets with him, Tony can tell that there is something wrong and gently tries to comfort her and asks her what's wrong. While Dr. Melfi knows that Tony would surely help her dispense justice to the man, she also knows that even though her attacker is a criminal and deserves to be punished, it would be equally wrong for her to send someone to attack and possibly kill him, and she decides not to tell Tony the truth.
After this, Tony and Dr. Melfi continue to meet, and their sessions together are always unique and interesting in different ways. Although Dr. Melfi may be tempted to believe Tony will never change, she is still compelled to help him. However, at the end of the series, Dr. Melfi is given advice by her own psychiatrist, Dr. Eliot Kupferberg, about the work that other psychiatrists' had done about sociopaths and their behavior. He advised her that, based on the findings of the psychiatrists, that by counseling Tony, she was actually aiding his criminal behavior and that, if Tony was indeed a true sociopath, there was no possible way therapy could help him other than to further empower him as a criminal and to give him new ideas.
Dr. Melfi is seen following up on this information and it seems that she is convinced of the information that she has been given. At her last session with Tony, she observes him tearing out a page from one of her magazines, and confronts him about it, ending with telling him that she can no longer help him. Tony is clearly surprised, and confused about why she would want to stop after having treated him for 7 years. She never reveals to him the information she learned, and Tony walks out of Dr. Melfi's office. Before leaving, Tony put's back the page he tore from the magazine and walks out. Dr. Melfi looks at Tony one last time before closing the door to her office.