"Wait, you're letting him stay home? I can't believe this. If I was bleeding out my eyes, you guys would make me go to school. This is so unfair."
Jeanie appears in the very first scene where Ferris is faking his sickness in front of his parents Katie and Tom Bueller. She asks what's going on, and when her mother tells her that Ferris is sick, she doesn't believe it because she knows what Ferris is capable of. Ferris then pretends to have blurry vision when she talks, and then she gets frustrated when her mother tells her to get to school. She thinks it's unfair that Ferris gets to stay home while she has to go to school. Ferris then tells her to not be upset with him, but she leaves and drives off.
She is later seen at school walking in the hallways when a girl walks up to her, and says that she's sorry about her brother and tells her that so many people have been saying that Ferris was very sick and "on the verge of death".
Later, she is skipping class and looks out the window to see Sloane Peterson get checked out by Ferris Bueller and instantly suspects that it's him.
Later, a boy is walking around with a soda can saying "Save Ferris" so the student body can raise money for Ferris' "serious sickness". Jeanie walks by, and asks "what", and he tells her that they're raising money to buy Ferris a new kidney, but Jeanie gets mad at him and knocks the can out of his hand.
She is later standing by herself in the hallways thinking about Ferris being "[allowed] to do whatever he wants, whenever he wants", but to not be too jealous since she got a car, and he got a computer.
Jeanie then skips Ms. Hagel's class to go up to the office to ask Grace if Mr. Rooney is available, but he has "left school grounds on personal business", when he actually leaves to catch Ferris, like she is. When she's about to leave, Grace asks if Ms. Hagel is expecting her in Consumer Ed class, and Jeanie says "probably", and then leaves.
Later, she is driving out of school in her car in frustration. All she says is "I hate him", continually showing her hatred towards her brother. She goes home around the same time Mr. Rooney is trying to get into Ferris' house to verify that he's faking his sickness. When Jeanie sees the "Save Ferris" slogan on a water tower, she instantly drives home, runs inside and bursts into his room to see that he really was skipping school. Then, she runs into her room to try and call her mom who is currently unavailable.
She hears the front door close, and goes down to the kitchen to investigate. When both Jeanie and Rooney sneak in the house believing that they both caught Ferris, they both jump out from their hiding spot, but when Jeanie sees that it's not Ferris, she freaks out, kicks him, and runs back upstairs. She calls the police to tell them that someone has broken into her house, but they think it's a phony phone call. She tries to convince them, but it doesn't work out, and slams the phone in frustration. When Rooney is washing his face in the kitchen, Jeanie goes on the intercom to inform him that she just called the police, and tells him to get out of her house. She also adds that she has "her father's gun and a scorching case of herpes".
Much later, she is sitting in the police station. A boy named Garth Volbeck is sitting next to her, and they talk for a while. She tells him everything that happened; Ferris skipping and Rooney breaking into her house. She also adds how much she hates Ferris. Garth tells her that her problem is her, and that she needs to worry more about herself than others. Then, she says that "if [he says] 'Ferris Bueller', [he loses] a testicle", and it surprises Garth since he knows him.
Katie Bueller is talking with the man at the police station desk, and is frustrated about the fact that Jeanie skipped school and talked about an intruder in her house. When she's done talking with him, Jeanie and Garth are kissing each other, and when Katie tells her to go home with her, Jeanie acted very flattered about meeting him, and says goodbye to him, not wanting to leave.
Jeanie and Katie are driving home, but Ferris runs in front of the car. When Jeanie sees Ferris, she speeds home, determined to get there before him, but she gets a speeding ticket. Katie talks to Tom about it when she is very frustrated at her when she speeds, and has to close off the deal from the Vermont family because of her. Then, when Ferris is caught by Mr. Rooney, Jeanie saves him from getting in trouble and tells Ferris that "[they were] worried sick about [him]". She tells him to get in bed, and talks to Rooney about Ferris running home from the hospital. Lastly, she tells him that he left his wallet in the kitchen, and slams the door only to smile when Rooney is getting bitten by the dog.
Jeanie is arrogant towards other people. She is also seen to be very jealous of her older brother Ferris Bueller since he always skips school and gets away with it, and fears that she could get caught skipping. Because of his actions, Jeanie suspects that he was skipping school instead of being sick, and even goes home to verify. And she is also known as judgmental, emotional, ambitious, negative, intelligent, eccentric, belligerent, uncompromising, evil, loathsome, loud-mouthed, egotistical and rude.
- She also goes by the name Shauna.
- Coincidentally, both Jeanie actors are named Jennifer.