Madison "Maddie" Rooney is the identical twin sister of Liv. Maddie also has two younger brothers and two parents that both work at the school she and Liv attend. Maddie is an outstanding student and school basketball phenomenon whose popularity is on the rise. That is until Liv makes a triumphant return to their Wisconsin High School. Maddie is more of the tomboy when compared to Liv.
- Her birth name is Madison.
- Maddie plays with her charm bracelet when she is nervous.
- "Bam! What?!" seems to be Maddie's catchphrase.
- Maddie and Joey are the only two people in their household to wear glasses.
- Maddie loves to win, and also likes to be competitive.
- It is unknown why Maddie and her twin Liv have blonde hair, while her parents and brothers have brown/black hair.
- The first time the girls pretended to be each other was when they were six.
- It is revealed that Maddie is the younger twin, as she was born on the 6th.
- She loves chicken pot pie.
- Her favorite restaurant is The Hoosegow.
- She is very sensitive at the heart
- She really, really, really likes her boyfriend, Josh.
- In "Home-Run-A-Rooney", she realises making someone happy is more important than always winning