Unlike most Auradon kids, she is much more open-minded about having the four wicked descendants attend their school, and is sympathetic to their plight. She is also friendly to them, and does not look down on them as wicked villains (unlike many others, even their teachers) Compared to the other kids, she is the most normal.
She is also strongly implied to be the individual who sets up the secret camera in the web series School of Secrets. Her voice appears at the beginning, saying "Alright. Good to go.", and at the end, saying "Be good, Auradon. Someone's watching."
She tells Mal, Evie, Carlos and Jay that whenever she was feeling sad, her mother would bake her chocolate chip cookies and make her laugh to cheer them up.
In the end the of movie, she was dancing with Chad Charming and then Carlos while Chad dances with Jane and then hugs Jay while Carlos hugs Jane and Chad hugs Audrey.
In Descendants 2, Lonnie is very strong willed and really wants to be a part of the Swords and Shields team, even thought its all-male. She also accompanies Jay and Carlos to the Isle of the Lost after she hears what happened to Ben. Her Martial Arts and sword fighting skills are shown and Jay takes an interest, making him step down as the Swords and Shields team captain and making her the captain. During the Cotillion scene, she is seen next to Jay, meaning that she is probably his date. She also sides with Mal when Ben comes to the Cotillion with Uma. At the end, she dances with Jay and shares a few moments with him.
Lonnie wants to be cool as she was the second person (the first was Jane) to ask Mal to use a spell on her hair to make her cooler. It's shown that Mulan and Shang are well off as Lonnie has no qualms about giving Mal $50 for a makeover. Lonnie is also shown as curious of the villains and under the assumption that their lifestyles aren't too different from her own. She's shown as kind and empathetic as she cries when she learns the villains may not love their kids. (In fact, only Evil Queen actually loves and cares for Evie)
Along with Jane and the other students at Auradon Prep, she was quick to turn on the 4 at the Family Day after Mal was confronted by Aurora's mother.
In Wicked World, Lonnie tries to be funny during the Neon Lights Ball, such as when suspicious events occur, treating the ordeal as if it were an actual movie. However, no one appreciated her humor.
In Descendants 2, Lonnie wants to be on the R.O.A.R. team at Auradon and really doesn't appreciate it when Chad Charming tells her that the rule book doesn't allow it. She seems to want to be in her mother's footsteps. Lonnie also appears to be very sneaky, especially when she overhears what happened to Ben on the Isle through Carlos, Jay, Duke, and Chad. She always is eager to help others, which is shown when she forces Jay and Carlos to take her to the Isle to fight Uma and the pirate crew.
Lonnie is a beautiful girl with her medium chestnut hair and honey highlights and brown eyes. She is seen smiling almost all the time. At the dance, Lonnie wears a short pink hanfu inspired dress with a green sash on the dance. Her go-to accessories are her bracelets and a headband.
Lonnie firmly establishes herself as a talented athlete and wants nothing more than to play on the all-male Swords and Shields team at Auradon Prep. Her request to be on the team is a joke to Chad Charming, who tells Jay that its all MEN. When Jay and Carlos come back to Auradon to make a fake wand (using Carlo's 3D printer), Lonnie overhears what happened to Ben at the Isle and forces Carlos and Jay to take her with them to help fight Uma. During the fight, she is seen to use her good nature and sweetness to defeat opponents and also has great skill when it comes to sword fighting. Because of this, Jay asks her to go to practice with him and makes her captain of the Swords and Shields team (because the rule book said "a team must be comprised of a captain and eight men" so Jay steps down as the captain and becomes one of eight men). At the Cotillion, it is seen that she is Jay's date (because he originally said he was going solo so he could dance with all the girls) and they share a few moments together. She also gets upset and supports Mal when Ben tells Mal he's in love with Uma. At the end, she dances with Jay.
Her made her first speaking appearance in "I'm Your Girl" where she was in the lab with Mal, Jordan, and Evie, making her an outfit. She thanks them for making her an outfit, although she wonders why they are making her dress in the science lab. When Evie says there's nothing more cutting edge than chemical compounds, Lonnie also says that she also wanted to look "welcoming". Jordan suggests that they should make it more fierce, and Lonnie chimes in by saying that she also wants to look more friendly. Lonnie is full of questions, asking if they want her to perform in the dark and wear a glow in the dark dress made of nuclear waste. Later at the hip hop show, she can be seen performing "I'm Your Girl", glowing in the dark as Mal and Evie turn off the lights.
- She, Jane, Doug and Ben might be the only kids at Auradon Prep who are fine with the villains' kids being at their school at first.
- Lonnie likes making cookies, doing hip hop dancing, and Martial Arts. Her Martial Arts skills are shown in Descendants 2.
- Lonnie also seemed to be afraid of Mal when she cast a spell to give Jane bad hair again, but must have become friends again because they were friendly at the coronation/dance.
- In a way, Lonnie is the eyes and ears of the viewers, as she often tries to understand more about the villains' kids, and asks common questions the viewers have about what their lives are really like.
- She was the main character in School of Secrets.
- Aziz appears to have a soft spot for her.
- She used to have short black hair and bangs before Mal spelled her.
- Lonnie apparently likes pumpkins as stated in "Mash It Up" when Jane makes pumpkins appear.
- In Rise of the Isle of the Lost, it is revealed that she has a brother that is older than her.
- Her name means "ready for battle" in old German.