Izzie is the oldest daughter of her mother's. She often takes care of her siblings, proven when she and Casey are given detention and she calls home to alert them that she will be taking some time to arrive, causing Casey to believe that she has a child. She tells Casey that her mother does not care for them as she should so she steps up at home, allowing Casey to open up about her relationship with Sam and her own parents and they bond.
Later, having become friends with Casey, shows up at her house needed comfort after she was forced to leave her home. Having taken her siblings to their grandparents', she did not want to intrude and Casey offers her to stay for the night. Later while she sleeps, Nate comes over and mistakenly believes Casey is into him and kisses her. Not wanting to cause a scene, she instructs Nate to leave and does not wake Izzie.
At school, Izzie finds Casey trying to leave a note in her locker (explaining what Nate did) and is confused. She walks off and confronts Nate, who lies and says Casey kissed him. Believing her boyfriend because she had known him longer, breaks off her ties to Casey, going as far as writing "Slut' and "Hoe" on her running shoes.
At Casey's party, Izzie shows up after being invited by Elsa Gardner. She follows Casey to her room after she becomes upset and tells her that she broke up with Nate, revealing she chose to believe him because she did not want to lose someone she loved, then says she cares very deeply for Casey and that she actually meant she was afraid of losing her, not Nate. As the two joke around about the proper way to make-up, they slowly lean in to kiss but are interrupted by Elsa opening the door. Izzie goes downstairs with Casey and looks upset as Casey kisses Evan.
When they hang out a few days later after Casey wants to stop avoiding Izzie, the two talk in the car. They laugh together and sit in silence while Casey declines a call from Evan, and Izzie reaches for Casey's hand, who holds her hand and they sit in silence again.
- Izzie was originally rude to Casey as she saw her as a threat, as Casey and Izzie were both attending because of their position on the track team and neither are like the rich kids who attend Clayton.
- Izzie is one of the first characters to possibly be LGBTQ+, as she and Casey almost kiss and later hold hands while alone.
- Izzie takes care of her three unnamed siblings; one of which is a baby.