- "Well, then why should we do anything more than once? Should I just smoke this one cigarette? Maybe we should only have sex once, if it's the same thing. Should we just watch one sunset? Or live just one day? It's new every time, each time is a different experience."
- ―Jane Margolis talking to her boyfriend
Jane was born on April 4, 1982 in Phoenix, Arizona.
Jane rents Jesse the duplex apartment next to hers after he tells her his parents kicked him out of his house. "D.B.A.A.," she warns Jesse, who can provide no references for his lease. "Don't Be An Asshole."
The two fall in love quickly, though Jane disappoints Jesse by brushing him off as just a tenant in front of her father Donald. She later shows contrition by slipping a superheroine drawing titled "Apology Girl" under his door.
When Jesse offers Jane a joint, she refuses, revealing that she's in recovery. But she later joins him as he smokes crystal to ease his guilt after his dealer and friend Christian "Combo" Ortega is killed by Rival Dealers. From there, Jane turns Jesse on to meth and heroin speedballs, causing him to miss Walt's meth deal with Gus. Jesse then lets her in on his situation with "Mr. White," who refuses to give Jesse his cut from a major deal until he gets clean. Jane takes the initiative to blackmail Walt into finally giving Jesse his half. "I just think if we had enough money nobody could make us do anything," she tells Jesse breathlessly. After getting Jesse's share, Jane tells Jesse that they will get clean and run away together - after finishing what heroin they have left. Jane wants to use the money to escape her father — she's promised Donald she'll go back to rehab the next morning.
Following a bar conversation about family with Jane's father - with Walt unaware of the man's relation to Jane - Walt returns to Jesse's home in an attempt to reconcile. While attempting to shake Jesse awake, Walt inadvertently flips Jane onto her back. Shortly afterwards, Jane begins asphyxiating on her own vomit due to an overdose. Walt considers saving Jane, but ultimately allows her to die before his eyes, knowing that her death will guard him from being blackmailed by her again, hoping to gain control over Jesse as a result, and possibly to save Jesse from the drug addiction that he believes was only strengthened by Jane. Walt then leaves to go back home to his family, including his newborn daughter ("Phoenix").
The next morning, Jesse awakes to discover Jane's lifeless corpse lying next to him. After a frenzied and unsuccessful attempt at revival, Jesse calls Walt in a panic. Walt tells Jesse to calm down and eventually contacts Saul Goodman. Shortly afterward, Mike Ehrmantraut arrives, cleaning the scene and helping Jesse prepare for the arrival of the police. Jane's body is taken away in the presence of a devastated Jesse and a strangely-detached, shocked Donald Margolis. Her apartment is shown when her father goes inside to pick a dress for her to wear during the funeral. Her voicemail is frequently heard when Jesse repeatedly calls it to hear her voice, but eventually the phone number is deactivated.
Her death manifests significant repercussions throughout season 3, and is largely responsible for Jesse's downward spiral throughout the first half of the season over his role in her death. Jesse is deeply tortured by grief and guilt about Jane's death. Walt also expresses guilt over his inaction towards Jane to Jesse, while under the influence of sleeping pills, and later questions the statistical improbability of both meeting her and talking to her father on the same night despite never having met either beforehand ("Fly").
Jane appears in a flashback in the eleventh episode of the third season ("Abiquiú"), having a discussion with Jesse about art at a Georgia O'Keefe exhibit mentioned in the second season. The two end up kissing in Jesse's Toyota, where Jane leaves a lipstick coated cigarette butt that Jesse later finds in his ashtray ("Fly").
Shortly after Hank Schrader and Steven Gomez are killed by Jack's White Supremacist Gang, Jesse is spotted by Walter and dragged away by Jack and his gang for interrogation. As retribution for being a factor leading to Hank's murder, Walt emotionally cripples Jesse by coldly telling him "I watched Jane die... I could have saved her, but I didn't." This also serves to imply that Walt could have saved Jesse (by not pointing out his hiding place to Jack) but instead chose his death as vengeance for Hank's death ("Ozymandias").
- "This is blackmail. Do right by Jesse. Tonight. Or I will burn you to the ground."
- ―Jane talking to Walt.
- Earlier versions of the script made Walt more directly responsible for Jane's death. In the original story Walt injects Jane with another hit of heroin while she's unconscious, murdering her. This was toned down to a version where he intentionally turns her on her back so she chokes to death on vomit. In the filmed version, Walt accidentally turns her while attempting to awake Jesse. She falls on her back accidentally and he chooses not to help her when she begins suffocating. Gilligan & Cranston on Jane's death (2010)
- There are notable similarities between Margolis and the titular character of the Jane's Addiction song "Jane Says,"
- There are also similarities between her and the character Mia Wallace from "Pulp Fiction". Both are similar in appearance and both had a heroin overdose.
- The Margolis name is a reference to the actor who plays Hector "Tio" Salamanca, Mark Margolis.
- Bryan Cranston has stated her death has affected Walter personally, not only as a father, but also the fact that it got to Walt's mind that he didn't do anything to save her.