Carlota's the oldest, and only daughter of the four Casagrande siblings, similar to how Lincoln's the only son of the eleven Loud kids (although Lincoln's the middle child while Carlota's the oldest child, similar to Bart Simpson, Lucy Van Pelt, and Violet Incredible).
The Loudest Mission: Relative Chaos
Around the time Ronnie Anne and Bobby reached the Casagrande residence, Carlota was having a fight with her younger brother, Carl, over the fact that Carl used her hair product without her permission. After their fight is interrupted by their mother, Frida, who mistakes them for playing sweetly together, the two fix their hair and walk away, still angry at each other. Afterwards, Carlota is seen carrying a pile of clothes while her dad is reading off facts from his book, she tells him that he isn't supposed to be doing "professor stuff", but he assures her that it isn't for work, it's for fun. A moment later, Carlota starts arguing about where they should hang the welcoming banners for Bobby and Ronnie Anne's arrival.
After C.J. notices Bobby, she, along with the rest of her family, greets the Santiago family. At the feast, Carlota can briefly be seen with her youngest brother, Carlitos, the two appear to be having a good time. After Hector, Bobby, Carlos, C.J. and Carl leave to go to the Bodega, Ronnie Anne wants to join them, but is stopped by Carlota, who doesn't think she should go to the "boring bodega" and instead takes her to get a makeover. She reveals that she bought dresses for Ronnie Anne at a local thrift store, and even bought matching pairs so they could match. Ronnie Anne tries to politely convince Carlota that it isn't her style, but Carlota interrupts her by spraying her with perfume, to "cover up the mothball smell". Afterwards, Frida takes a picture of the two, saying they already look like sisters, much to Ronnie Anne's confusion. Carlota then decides to wax her legs, to get her mind off what Frida just said.
Later, after Ronnie Anne just finished eating a meal prepared by Rosa, Carlota decides she should pierce Ronnie Anne's ears, though quickly changes her mind to belly button. Although she got in an argument with Rosa and Frida, as soon as "The Dream Boat" began airing, she, along with the entire Casagrande family, plus Bobby, rushed towards the living room to watch it, to which she remarks that "Karen" should send Brock overboard, since he has no style. After Ronnie Anne goes to the bathroom to get some along time, Carlota barges in, informing her that "Blaine" walked the plank.
The next day, after Lori and Lincoln arrive at the Casagrande residence, Ronnie Anne pulls aside Carlota and ask her to do a make over. Carlota assumes that Ronnie Anne is referring to giving her a make over, which prompts Carlota to say that she's going to throw away Ronnie Anne's clothes, since no one would want them, even if she did donate them. Now annoyed, Ronnie Anne tells Carlota that she wants her to give Lori a make over, not herself, which leads to Carlota trying to take her words back, even saying that Ronnie Anne has an unique, "rugged" look. Despite the misunderstanding, Carlota goes along and gives Lori a huge make over.
Later, Carlota picks out a selection of hoodies for Ronnie Anne and hangs them up in her new room as a welcoming gift. This, along with the other heartfelt presents convinced Ronnie Anne that she wanted to stay with the Casagrande's. Only moments later, as the Casagrande residence get's attacked by the gang of cats, Carlota assist Rosa in trying to knock away the cats with brooms, but gets chased off by the cats instead. Once Maria traps the cats in another room, she starts to laugh at the cake falling on Ronnie Anne, though not in a condescending way, but in a friendly way.
The Casagrandes are getting ready for Lincoln and Lori's visit to the city, and Carlota searches for Ronnie Anne (who is hiding from her) to try out one of her dresses.
Carlota later helps dress up Lori for her time visiting downtown.
She has a lot in common with Leni, such as caring about fashion and appearance, but unlike Leni, she isn't ditsy. She's into makeovers like Lola, and loves to try and get Ronnie Anne to change her appearance. She appears to be a kind person, showing sisterly love towards Ronnie Anne, and is generally friendly around her family, as well as Lincoln, but gets agitated when her brother Carl gets into her cosmetics. She was also shown to be a charitable person, as she apparently donates clothes she no longer wears. She seems to be good with kids, as she was seen having a good time walking with Carlitos, her youngest brother.
Carlota is a plus-sized Latin American teenage girl with two pairs of eyelashes, and long black hair, with some strands styled into a pony tail. She wears golden circular earrings, magenta lipstick, a light green dress with a white collar, orange bracelets on each wrist, pink socks, and brown boots.