Known as Louisa Ballinger. She has lived in Chicago her whole life and has been best friends with Maddie since she was five.
Louisa has shoulder length blonde hair and beautiful blue eyes. She is in eighth grade, and is thirteen years old. She also has a tan.
Louisa is oblivious to what is happening around the world, as she believes that everything is perfect. This is also why she always takes things for granted, because she was raised in a rich and wealthy family, and pities herself for not having freedom due to her parents' over-protectiveness. Louisa loves Country Manor School and has no problem with it. She does not realize why everything has to be for her own safety, but besides that, she couldn't love CMS any more than she already does—whereas Maddie couldn't hate it any more than she already does. While they were at CMS, Louisa and Maddie had fought a lot, and it was a little hard to believe that they had been best friends since they were five years old.
In Madeleine Frye's opinion, Louisa is a brave girl, as she quotes: "I find myself wishing I could be as brave as Louisa". Indeed, she is courageous, as shown when she volunteers to accompany Maddie on the trek to her apartment in the fourth book, Set Me Free. However, when both girls are forced to jump from the apartment window, Maddie takes the lead, which suggests that she is trying to be brave and is successful, while Louisa hesitates before jumping.
Louisa is sweet-tempered and seldom angry. Her only notable "eruptions" are when she gets impatient with her roommates (though rarely), and once when Maddie tried to stop her from reuniting with her mother. In that occasion, Louisa used quite harsh words and did not bother when her words made Maddie cry, though she apologized sincerely after that.
Besides that, Louisa is also a great healer, as shown when she produces the knowledge to clean and flush cuts and wrap bandages. She did a great job in healing Drew's shoulder and Alonso's ankle. Her knowledge of healing may come from her parents, who are both surgeons.
Louisa is boy-crazy, although she does not admit it. In the first book, Behind The Gates, Louisa waves to the boys across the river in another school, though she knew that it was strictly forbidden, as Mrs Brewster had stated clearly. In the second book, Run For Cover, she is the one who keeps trying to make Rosie let her "keep" the boys, as shown with this description by Rosie:
"If you won't let us come with you, we'll run away on our own," Ryan says.
This sounds like a fine plan to me, but Louisa immediately jumps in. "Don't be silly. We want you with us. We'll be safer if we stick together." Which is blatantly false, but I'm guessing she doesn't want to hear about how a large group will make more noise crashing through the woods, or how much easier it will be to spot us all from helicopters, or how much harder it'll be to find somewhere safe for us all to sleep, never mind finding food for seven instead of four. Safer! We might as well turn ourselves in now. But I guess when it comes to boys, she can't even think straight. I should have learned that on our weekend trip when she sided with them over me.
"Right, Rosie?" Louisa says. "I mean, look at these poor, helpless guys. They obviously need us."