Elle's first chronological appearance is in "Four Months Ago…". During this time, the Company made Peter Petrelli their willing prisoner and in those months he was held, Elle seems to have developed a crush on him. Peter confesses that he likes the little jolts which Elle gives him as a tease and kisses her. She confides in Peter that she has lived in the Company's holding facility for 16 years. She also admits to being diagnosed as a sociopath; she explains at age six, she accidentally set her grandmother's house on fire and at age eight, caused a major blackout in Ohio. When he escapes from the facility, Elle is upset and angry to the point that she blasts him, setting him ablaze during his escape.
Elle first appears in the episode "Fight or Flight" searching for Peter in Ireland. Peter has no recollection of his past and is staying with the owner of Wandering Rocks Pub, Ricky. Elle questions Rick about Peter's whereabouts and when he pretends not to know Peter, she kills him with a large bolt of electricity on her way out the door. Later on, during a telephone conversation with Bob Bishop, her father and Company head, she dismisses the murder as trivial and insists she can find Peter. However, she is pulled off the assignment, much to her frustration.
In "Cautionary Tales", Elle came back to the United States. Former Company employee Noah Bennet, captures Elle for collateral as Bob had managed to capture his daughter, Claire. He ties her hands to a chair and ties her bare feet together and puts them in a dog bath. Elle tries to use her abilities while in the dog bath, but she shocks herself. During this time, Noah tells Elle that Bob allowed the Company to perform tests on her which had begun as early as the age of seven. This included subjecting her to high doses of electricity, which scarred her emotionally for life. Elle has no recollection of the tests, and Noah suggests the Haitian had a role in causing Elle to forget her experiences. After an agreement is made, she is reunited with Bob and Claire momentarily reunited with Noah. However, Elle attacks Claire and West as they leave. She tries to attack Noah, but he shoots Elle in the arm before she can hurt him or anyone else. As it seems Noah is going to kill Bob, Mohinder Suresh, a scientist working with Noah and the Company, shoots and kills Noah. She leaves with Bob and Mohinder, giving Bob a look of distrust.
In the episode "Truth & Consequences", Bob chastises Elle for allowing West and Claire to escape. He then assigns Elle to perform surveillance on Claire and her family as they prepare to leave town. Claire, however, spots Elle from a distance, leading to a physical confrontation.
Elle's last appearance in season two is in "Powerless". Her father reprimands her for her mistakes; to redeem herself, she attempts to re-capture the now powerless Sylar for the Company. She uses her ability to confront Sylar in Mohinder's research lab, but Sylar is armed with a gun and shoots at Elle. Sylar manages to slip away, leaving Elle unharmed. She comes out somewhat defeated, but is informed by Mohinder that if not for her arrival, Sylar would have killed him, Maya Herrera and Molly Walker. He says the three of them owe her their lives, to which she replies, "Cool".
The episode marked Bell's previously expressed interest in performing in scenes with the character Sylar, as she and Zachary Quinto have been good friends for almost ten years. Bell had said that she "would love to see him and Elle face off one day". In November 2007, Bell and Quinto filmed scenes at a restaurant in Los Angeles, which was set as a "New Jersey Diner" and had involved police and paramedics. The filmed scenes are part of the untold stories which are a special feature of the season 2 dvd set.
Following her failure to stop Sylar, Elle seeks assistance from Noah Bennet, detained in Level 5, a high security ward for the Company's most dangerous prisoners. However, Sylar is already there, having killed her father. He attempts to take her ability, but the pain of being scalped causes her to involuntarily release a massive electrical surge. This knocks Sylar out, but also disables security for the entire facility, allowing the prisoners to escape. Elle is later fired by Angela Petrelli – the new head of the Company – who tells Elle that the only reason the Company kept her was because of her father's influence.
Elle makes her way to Claire's house to seek help from Noah, having lost control of her ability. She attacks Claire out of anger, but is subdued when Lyle throws water on her. She says that Daphne told her Pinehearst could help her with her condition, so Claire agrees to escort her there. They reach Pinehearst just in time to see Peter Petrelli thrown from a seventh story window. Claire takes him away from the building, but Elle refuses to leave after learning from Peter that they can take her powers away.
In the episode "Villains", Elle's life a year earlier is explored, revealing that she had been partnered with Noah Bennet at one point. The two are assigned to watch Sylar (still Gabriel Gray) in order to discover how he transfers abilities. Elle saves Gabriel after he attempts to kill himself out of guilt for killing his first victim. She is told to befriend him, and Gabriel develops an attraction to her that suppresses his hunger. Using a list of people with abilities Gabriel had compiled, Noah arranges to introduce Gabriel to one of them to see his power in action. However, Elle does not agree with the plan, revealing she has developed feelings for Gabriel. Nonetheless, she is left with either going along with the plan or being fired. She reluctantly goes along with it, introducing him to Trevor, an evolved human with a kinetic projection ability. Her repeated references to Trevor being "special" anger Gabriel, and he orders her to leave while he kills Trevor. Elle is left with guilt as she caused an event that helped to create "Sylar".
In the following episode, Arthur Petrelli arranges for Sylar to speak with Elle in order to teach him how to use his latent empathic abilities to take powers, rather than doing so through killing. Elle is chained to the floor in a metal room, still in pain from her ability. She repeatedly attacks him, furious at Sylar for her father's murder, eventually begging him to kill her so that her pain will go away. He forgives her for turning him into a monster and convinces her to forgive herself for her crimes, wanting to take away her pain without killing her. At that moment, Elle's pain disappears and she regains control of her ability. Likewise, Sylar is able to absorb her power. The two appear to rekindle their old feelings for each other as Elle teaches Sylar how to use her ability.
In "The Eclipse Part I", she and Sylar are sent to retrieve Claire who is the catalyst. At a car rental store, Elle challenges who Sylar is a killer or a daddy's boy. Sylar proves to her that he's a killer and they head out to find Claire. They soon find her at Stephen Canfield's house where a fight ensues. Elle and Sylar find themselves powerless because of the eclipse. Elle aims a gun at Noah but Claire jumps in and takes the bullet. Noah knocks her out and dislocates Sylar's arm. Noah escapes with an injured Claire. They wake up and Elle relocates Sylar's arm. Sylar explains to a shocked Elle that losing his abilities is a bit of a relief. She tells him that they can't just take what they want anymore, then Sylar grabs Elle and kisses her passionately. Outside, they are being aimed by a rifle by Noah Bennett.
 In Heroes graphic novels
Elle also appears in the Heroes webcomics. Her appearances in the online series occur before her introduction on the television series. Elle's first webcomic appearance is in "Elle's First Assignment, Part 1", which reveals her first assignment for the Company. Elle monitors Claire Bennet, posing as a student at Union Wells High School. After following Claire home, Elle ends up confronting Eden McCain. The incident is broken up by Noah Bennet, who informs Elle that he doesn't "want [Elle] hanging around his daughter any more". In Part 2, she finds out about the tape of Claire testing her power and tries to take it from Zach. She is stopped by the Haitian and Mr Bennet, who find out about the tape as well. Elle also appears in "The Man With Too Much Brains" to recruit the original webcomic character Matt Neuenberg to the Company. She also was teamed up with Thompson Jr. to capture Donna Dunlap, a woman with enhanced vision.
In "Eris Quod Sum, Part 1", it is revealed that she has lost control of her ability since leaving the Company, so she has gone to London to find help from Claude. After she tracks him down, he confronts her but then runs away. It begins raining, and Elle decides to take advantage of it. She releases an electrical charge, which travels through the water on the ground and into Claude, but she, too, is knocked unconscious in the process.
 Powers and abilities
Elle has the ability to generate and manipulate electricity, discharging and directing it as electrical arcs. She has been shown being able to weld a lock, blast objects, knock people unconscious, and even kill a man. She is not entirely immune to the electricity she produces, however, as shown when she is drenched in water and attempts to create electricity — she gives herself an electric shock, causing great pain. Elle has endured a series of testing by the Company during her childhood that measured the extent of her power. Bob had stated that Elle was in a "different league" when comparing her to Claire. When inquiring about her abilities, Elle was able to learn from Noah Bennet that the Company had wanted to record the extent of her abilities (whether she could power a flashlight, a street lamp, or an entire city block) and Bob had often prompted to continue the tests further, even after Elle had passed out.