- "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 a 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, despite Jane angering Jesse by brushing him off as just a tenant in front of her father. 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 and has been clean for over a year. But she later joins him as he smokes crystal meth to ease his guilt after Christian "Combo" Ortega is killed by the Rival Dealers. From there, Jane turns Jesse on to meth and heroin speedballs, causing Walt White to nearly miss a major meth deal with Gustavo Fring. Jesse lets her in on his situation with Walt, who refuses to give Jesse his cut from the deal until he gets clean, until Jane blackmails him. After getting Jesse's share, Jane tells Jesse that they'll get clean and run away together after finishing what heroin they have left. Jane wants to use the money to escape her father, who found out she relapsed.
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, hoping 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 lets her die, knowing that her death would help him gain control over Jesse as a result, and possibly stop Jesse from using drugs.
The next morning, Jesse sees Jane's lifeless body 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. Her apartment is shown when Donald picks 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 it is deactivated.
Jane's death had significant repercussions, and is largely responsible for Jesse's downward spiral throughout the first half of the season over his role in her death. Walt also expresses guilt over his inaction towards Jane to Jesse, and 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'Keeffe 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").
- "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 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)
- Despite being a tattoo artist, she had no tattoos of her own.
- 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. Although Vincent was able to revive Mia, Jesse was not able to revive Jane.
- 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 because he didn't do anything to save her.
- In Jane's Apartment can be seen a black-and-white picture of a woman hanging on the wall. Viewers might assume it’s a photo of Jane’s mother, but it’s subject is the American poet and painter Elizabeth Bishop. The fact that Jane has a famous artist’s portrait hanging on her wall, but none of her own family, seems to suggest her strained, tempestuous, relationship with them. The choice of Bishop is certainly also helped by the fact that she’s Vince Gilligan’s favorite poet.