- "It's hard, when you love someone. You see the person that they were, the person they could still become. You close your eyes to the truth."
- —Leslie Thompkins to Nora Fries[src]
Leslie Thompkins is the widow of Mario Calvi and a former medical practitioner in the female ward of Arkham Asylum. She later becomes the medical examiner at the Gotham City Police Department, Jim's second ex-fiancée and the mother of their unborn child. However, after Jim is framed for murder and imprisoned, Leslie loses the child and temporarily leaves Gotham City.
Meeting Jim Gordon
A doctor in the female ward, Leslie was called over by Director Gerry Lang to look at a male patient that had electroshock therapy performed on him by an unknown assailant, meeting Officer Jim Gordon while doing so. Forming a friendship with him, she later examined yet another patient who had electroshock therapy performed on them, catching Jim and Dorothy about to go into the basement of Arkham Asylum, she asked to join them, though her request was rejected by Jim, who told her to leave as he suspected Dorothy was the one performing the electroshock therapy, with Dorothy escaping from them. The two later escaped a mob of inmates who were chasing after them, after being freed by Dorothy.
Leslie tells Jim about an inmate who curses dolls of people for inmates, giving a doll resembling Sal Maroni.
Leslie was called by Jim to help him on a case, though she arrived dressed up, and he confessed to her that he had just used the case as an excuse to see her. The two then kissed before Gordon had to leave.
Working for the GCPD
Leslie and Jim concluded their third date, with Leslie informing him that she was hired as the new medical examiner of the GCPD, much to Jim's surprise. The next day she arrived for her first day at work, and was shown around by Captain Sarah Essen. Leslie later invites Jim to the circus, and Jim once again reminds Leslie of no PDA in front of their peers, and she reluctantly accepts the condition.
Leslie and Jim shared a date together at Haly's Circus but the date abruptly ends when clowns burst onto the scene led by Owen Lloyd who engages Alphonse Grayson. Though Jim was unable to find out anything, Leslie manages to find out through John Grayson and Mary Lloyd that this the confrontation between the two members of their families, had been about a snake charmer named Lila Valeska. Fearing that something might have happened to the woman, Leslie and Jim visit her son, Jerome Valeska, to find out the whereabouts of his mother. Jerome's concern for his mother and him not knowing anything about the whereabouts of his mother, coupled with the suspicious attitude ringmaster made Jim suspicious, and using her snake to guide them, they soon after manage to find Lila's dead body covered by a blanket. Later at the GCPD, an elderly, blind, psychic, named Paul Cicero arrived before Leslie and Jim to deliver a message Lila had supposedly sent him from beyond the grave. While Leslie considered that it might have some truth, Jim however, skeptic. That night at Leslie's apartment, she and Jim have dinner, and she is excited by the message Paul Cicero had brought them earlier, and her wits she manages to decipher the message, as it referred to a park located under the Arkham Bridge. Humoring her, mainly because of her insistence, Leslie and Jim visit the park at night and to the surprise of them both of they immediately find an old ax blood covered with symbols carved into the handle. Leslie is later present when Jim interrogates Paul Cicero and Jerome Valeska and had figured out that the latter had killed his mother, and Cicero had assisted him.
When Leslie sees the report of the case Jim was investigating, she is horrified to discover that the victim, Grace Fairchild, is close to her age, and was last seen alive in a bar located in her neighborhood.
At her apartment, Leslie hears a strange sound in the middle of her bath. After exploring she discovers that the intruder was actually a cat, but she quickly turning around and accidentally hits Jim, in the spur of the moment. Later, after being tended to, Jim tells Leslie the truth about the Ogre and how this case came into his hands. She is asked to leave town, but she refuses knowing that Gordon could catch him. He then confesses his love for her and the two kiss.
At the GCPD, Leslie asked Jim when was the last time he slept or ate, and Leslie reminded him that Barbara's kidnapping was not his fault, but Gordon told her that anything that happened to Barbara would be his fault. Later after Gordon rescued Barbara, Leslie congratulates him and confesses that he thought he would blame himself for protecting her, and not remembering Barbara and that than whatever the two of them had would be dead.
In the medical examiner's room, Leslie gave Barbara an examination. After concluding that Barbara had healed physically after her encounter with the Ogre, Dr. Thompkins recommended that Barbara received trauma therapy, to the discomfort of Jim. Barbara keeps asking Leslie to be her therapist the doctor reluctantly agrees to do so. Leslie met with Barbara for therapy at her penthouse, where she confessed her fear of one day waking up and discovering that Jason was still alive. At one point, Leslie is told by Barbara having felt more frightened by Jim during their first date, then she was of Jason. She surprisingly asked if Jim ever hit Leslie, though the latter denied him doing so. Leslie continued asking about Barbara's experience with the Ogre. Under the guise that she had told Leslie some of her secrets, Barbara asks Leslie if Jim had told her that he had loved her. Leslie said no, and Barbara tries to get more details of their relationship, however, Leslie refocuses on the matter at hand. Soon after, Barbara confessed to Leslie that she had really killed her parents, and starts chasing Leslie around the penthouse with a knife, forcing Leslie to seek refuge in the bathroom where she tries to make an emergency call. Barbara manages to break open the bathroom door and lashes out furiously against Leslie. Both engage each other in battle, throwing each other until Leslie finally manages to knock Barbara unconscious after hitting her head against the floor. Gordon, Bullock, and Falcone then enter the penthouse, with Leslie and Jim embracing while Leslie explained what had happened.
Leslie is told of Jim's firing by Loeb. Jim realizes she's happy he got fired, though Leslie told him it was because she knows he will keep fighting. Later, Barbara calls Gordon, trying to convince him Leslie lied about what had happened the night the two fought. Gordon hangs up and Leslie asked who it was. When Barbara called Leslie's home phone, Gordon admitted it's Barbara. Barbara leaves a voice message, telling Leslie she wishes she would die screaming. Leslie tells Gordon they should leave Gotham and start a new life, though Gordon says they can't due to him doing an unlawful action. She later attends Commissioner Loeb's retirement ceremony with Jim, and afterward is informed by the newly appointed Commissioner Essen of the Arkham inmates break out, which included Barbara Kean.
At the Gotham Children's Hospital Gala, Leslie encounters Bruce Wayne and Alfred Pennyworth. During the show, Leslie eventually recognizes Barbara and calls Jim, but she was taken by one of Galavan's henchmen. While Jerome is terrorizing the hostages, Barbara taunts Leslie telling her that she and Jim will get back together in a year and will tell their grandchildren about how a "Man eating harpie" almost tore them apart. Leslie kicks her and Barbara tries to stab her in retaliation, but Jerome stops her saying it hasn't been 10 minutes yet.
Leslie convinces Jim to have a double date with Nygma and Kristin Kringle that night at their home. During the date, Leslie notes that Ed is more relaxed, lively and cheerful and even offers up a toast to their friendship. After the date was over, Leslie and Jim discuss the Galavan's proposal.
In the archive room, Leslie and Kristin Kringle had a conversation with each other. Firstly discussing Tom Dougherty, Kristin then moved onto her relationship with Ed, telling Leslie that he was too gentle and that she felt as if he was holding something back from her. Later at her apartment, Leslie sat with Selina Kyle who had a gun pointed at her.
Leslie later gives Jim a key to her apartment as she didn't like getting up late at night to unlock the door for him. She later arrives at the medical examiner's lab, and finds Nygma who invites her to go and grab some coffee so Leslie could give him some advice.
Leslie agrees with Captain Barnes about Jim going after Galavan without the proper evidence. When Barbara arrives at the GCPD and offers to show Jim something in exchange for giving him information, Leslie strongly protests as she advocates for Barbara being sent to a hospital as quickly as possible to resume her treatment. Before Jim left, Leslie and Jim had an argument, as Leslie told Jim that Barbara had sucked him back in and that his and Barbara's sickness fed off of each other. Leslie was later kidnapped by Tabitha Galavan and brought to Gotham Cathedral and tied to a wheelchair. Barbara tries to tell Leslie who Jim really was. As proof of good faith, Barbara confesses the location of Mayor Aubrey James. She then asks Gordon to admit to something, though when he questions Barbara as to who kidnapped Mayor James, she asks Lee whether she knew how he got reinstated at the GCPD. Leslie surprises her by telling her that she knew Jim had killed a man for Penguin. Barbara then held a knife to Lee's face, telling the latter that she would prove that she loved Gordon more by carving Leslie's face off of her skull. However, Leslie distracts her by asking her where she got her wedding dress from, allowing Gordon who had been filing the ropes holding him with the pipe on the chair, to break free, and grabs the shotgun Barbara had previously wielded. While Jim freed her, Leslie informed Jim that Barbara was escaping. Later, Leslie informed Jim that Barbara's life was saved thanks to bushes that broke her fall, but she sustained half a dozen broken bones and was in critical condition.
Leslie intercepts Jim on his way to Galavan's penthouse, and given the recent events that occurred, it had shown Leslie that Jim was finding ways to give in to his inner darkness which worried her. Later, Leslie tended to Jim's wounds and asks him to always tell the truth. Gordon's phone then began to ring, and Leslie answered it, with Detective Alvarez informing her of the death of Officer Parks at the hands of Eduardo Flamingo.
Leslie performed an autopsy of the monk's body and later questioned Ed as to Kristin Kringle's whereabouts.
In an attempt to prevent Jim from helping Oswald Cobblepot go after Theo Galavan she revealed that she is pregnant with his child and tries to persuade him to leave Gotham with her. However when Jim finds out from Alfred Pennyworth and Harvey Bullock that Bruce Wayne has been kidnapped by Theo to be killed by the Order of St. Dumas, he decides to help them go after Theo. Leslie then leaves. After Jim deals with Theo, he reconciles with Leslie and proposes to her.
Leslie goes home with Jim after he's cleared of all charges for the murder of Theo Galavan.
Leslie visited Bruce Wayne at the call of Alfred, who feared that Bruce was suffering emotional trauma after his abduction. With a lack of emotion, Bruce confessed he was more determined than ever to find the murderer of his parents. Leslie tells him that he needs closure, not an unhealthy obsession, but at that point, Bruce ends the conversation and states that perhaps they could do it again at some point. Leslie is later informed that Nora was being transferred to Arkham, to use as bait for her husband, Victor. She is eventually convinced that it was the best option, but everything doesn't go as expected when his Leslie decides to accompany as Nora she was refused to leave her patient. There, Ms. Peabody escorted Leslie and Nora to the medical wing of the asylum, where to Lee's displeasure held Barbara Kean who was in a coma. Leslie was later asked to prepare Nora for transfer by Gordon. Suddenly, Victor appears and Leslie offered to provide her services as a doctor, which Victor accepts. At the Fries home, Leslie was asked by Nora to get her some water. A few seconds later Victor returns with the necklace and after a kiss, he freezes her. Upon discovering that Nora had changed cartridges in the gun Leslie is asked by Victor to tell the police he would surrender without resistance. Later at her apartment, Leslie is informed by Jim that Victor Fries had died in Arkham's infirmary. He then berates her for the danger that their baby at risk, but she makes him see that he put their child in danger when he decided to use Nora as bait. However, Gordon points out that putting her there was Captain Barnes' idea, and it was good police work. Leslie then told Jim that she did not believe his story about what had happened to Galavan, and emphasizes that Jim lied to her. 
Leslie goes to Jim to ask him to find out the whereabouts of Kristin Kringle since she hadn't received her last paychecks, and Leslie was afraid that Tom Dougherty might have hurt her.
In Atlanta, Mario met Leslie and eventually got into a relationship with her. When Jim decided to leave Gotham City in order to find her, he tracked down her address and arrived with flowers in hand. But while peering through the window, he saw Mario and her together. Broken, Jim departed without letting her know about his visit and returned to Gotham City.
A few weeks after leaving Gotham, Leslie moved on from Jim and found herself a new partner. After Jim decided to leave Gotham City in order to find Lee, he tracked down her address and arrived with flowers in hand. But while peering through the window, he saw her with her new partner. Broken, Jim departed without letting her know about his visit and returned to Gotham City, where he decided not to return to the GCPD and instead became a bounty hunter going after monstrous escapees from a facility known as Indian Hill.
Six months later, Leslie arrived back in Gotham by train.
When Jim Gordon first met Mario Calvi at Gotham General Hospital, he mentions how Leslie has talked about him. At a restaurant, Mario later tells Leslie about his encounter with Gordon. They are then visited by Mario's father Carmine Falcone who talks to Leslie about his son's history. He then does a toast to their relationship.
Leslie is later abducted by a deranged Jervis Tetch as part of his revenge game against Jim Gordon, Mario arrives at the precinct where he crosses paths with Gordon about to leave. Gordon received a clue about Leslie and Valerie Vale's whereabouts from the "White Rabbit", which was the home of Mario and Leslie. As Gordon goes inside to join Tetch, Leslie and Valerie at his "tea party", Mario sneaks into the cellar to retrieve his gun. After Mario was stopped, Jim is told who he should shoot. When Jim quotes "Kill Lee," Tetch shoots Vale. After Tetch, Dumfree Tweed, and Deever Tweed get away, Mario gets to work in the emergency room to perform surgery and save her life. While Gordon and Leslie wait, Leslie assures Gordon that Mario is a good surgeon and will save her.
Leslie told Mario that Jim told Jervis to kill her because he knew that Valerie would get shot instead, meaning that he actually saved her life that day. Mario told Leslie that he wanted Jim out of their lives.
While leaving a restaurant with Mario and Carmine, Leslie witnesses the valet get killed by a car bomb that was planted there by the The Court of Owls. After seeing Leslie leaving Gordon's apartment, two punks came up behind him and started messing with him only to be brutally taken down by Mario. It is then shown that Mario was infected by Alice Tetch's blood.
Jim knocks Victor Zsasz out to get his weapon back and makes his way to the church in order to warn Leslie about Mario being infected, but it is to no avail. Before leaving, Leslie asks Carmine to have Gordon removed from the church. When the wedding starts, Mario watches as Carmine escorts Leslie to him as they exchange their vows as Gordon is beaten up by Carmine's men. They are pronounced husband and wife by the priest. At his father's lakeside house, Mario thanked Leslie for sneaking them out of the reception. When Mario asks her if she still cares for Gordon, Leslie states that she loves Mario, but she will always care for Jim. Jim visited Carmine asking for the location of Mario and Leslie while telling him what happened to Mario. Carmine tells Jim that he will give him the location only if he promises to bring Mario in alive. Jim promises and is given the location. When Gordon heads to Carmine's refuge, he sees Mario with a knife in hand, seconds away from stabbing Leslie. Jim stops Mario by shooting him twice in the chest in self-defense. Though some of Mario's blood got onto Leslie's cheek.
Leslie is intelligent, kind, caring, selfless, has a moral compass, and is unafraid of being around the dangers that Jim Gordon brings as a police detective. Since getting engaged into the Falcone Family through Mario Calvi, Leslie seemed to develop a more arrogant if not bitter personality. Not afraid to use her connections into the family for her own ends as proven when she punched and later threatened Edward Nygma in retaliation for Kristen Kringle's murder.
Her relationship with Jim seems to have diminished, as he tried to warn her not to marry Mario, as the latter was infected with Alice Tetch's blood, she didn't believe him and believe he was trying to sabotage her relationship with Mario out of jealousy, despite the fact that Jim would never do something like that, she found out the hard way that Jim was right about Mario being infected, when he killed the former in self-defense.
Even after Mario was revealed to be infected by Alice Tetch's blood, she blamed Jim for Mario's death (refusing to acknowledge that the former was right about her husband) and wanted him arrested, however Harvey refused, as he defended Jim's actions, even Lucius Fox pointing out that Mario would have eventually gone on a killing spree, Carmine Falcone believes Lee is using her anger towards Jim, to hide the fact that that she still in love with the latter. When Lee visited Nathaniel Barnes who is also infected by Alice Tetch's blood, she was horrified not only by how much the virus has changed him, but also realize that Mario would have ended up the same way like Nathaniel.
- High-level intellect: Leslie is very intelligent.
- Expert medic: Leslie is shown to be an expert in medical care, as she has been a doctor for an unknown number of years.
- The character was created by Dennis O'Neil and Dick Giordano. She first appeared in Detective Comics #457 (March 1976) where she was depicted as a friend and fellow medical student of Thomas Wayne while later serving as the personal doctor of Batman.
- This is the first live-action incarnation of the character Leslie Thompkins.