At 17 years old, Lori is the oldest child of the Loud family, and the oldest of Lincoln's five older sisters. This is a fact she uses to assert authority and absolute dominance over her siblings. Her most annoying habit is using her phone and texting to Bobby all of the time.
Lori is bossy, condescending, and has the second nastiest temper after Lola. But aside from that, she is also cute, friendly, and protective. As the oldest sibling, she is supposed to act responsibly and mature, but sometimes she doesn't act like it, and instead she behaves like her youngest sisters, like in "Left in the Dark", where she's afraid to go down into the dark basement.
She likes to keep her shoes under the bed for unknown reasons. She doesn't like the others touching her possessions, especially her cell phone, which seems to be her most valuable object. The reason for this is that she doesn't want to waste her phone memory for messages other than the ones from Bobby. She's also very territorial as she loudly yells at anyone who goes into to her room without permission before kicking them out.
In some occasions she acts without thinking, and commits malicious actions against the others for her own selfish benefits, like in "Driving Miss Hazy", but since her love for her family always comes before any petty problem, she has a caring heart underneath a rough exterior, and she will always try to fix her mistakes.
"Lori Loud is 'literally' the oldest of the Loud children. She's the self-proclaimed boss and the only sister with a driver's license...so it pays to stay on her good side. A professional texter and avid eye-roller, Lori is never afraid to tell people how she feels."
Lori is the tallest sibling of all, and like Leni, she has breasts. She has large blonde hair (a genetic trait she shares with her mother, even though her hair is longer). Her original design depicted her with pink eye shadow, a white tanktop, navy blue shorts, and black shoes. Later it was changed with a light blue tanktop, brown cargo shorts, blue slip-on shoes, and blue eye shadow. She also wears pearl earrings.
Her nightwear includes a sky blue nightshirt, and blue slippers, but later, her current one contains a white tanktop, and small blue and white shorts, with a square pattern, as seen in "Space Invader" and "Overnight Success". Her swimsuit is a two-piece blue bikini.
In "Come Sale Away", it's revealed that she used to wear braces, a blue ribbon, and previously suffered from acne.
Her phone is a handheld object owned by her. She often talks to her boyfriend Bobby with it, but she also talks to other people from time to time, and text with it as well. A common animation goof with her phone, is that it changes colors at times.
In the alternate universe where Lincoln has ten brothers instead of ten sisters, Lori is a boy named Loki Loud. Unlike Lori, Loki is even more selfish, greedy, and is very bossy around the others. He is also mean and abrasive towards Lincoln, and mocks him for Luke (Luna) using him to clean the toilet, Leon (Lily) for biting his thumb when he gets a "boo boo", and teases him about Ronnie Anne.
However, in the dimension where the sexes of the Loud kids are the exact opposite (meaning that it's one girl and ten boys), Loki's shown to be very caring and protective of his sister, Linka--in fact, Loki's the first of the brothers to ask Linka (technically Lincoln-in-Linka's-body) if she's okay after he and the rest of the brothers heard her screaming in the middle of the night.
Loki eventually ceases to exist when the whole adventure was revealed to be a dream, which Lincoln wakes up from it at the end of the episode.
The High Card
In the minicomic Deuces Wild!, Lori takes on the super heroine identity The High Card. She is one of Ace Savvy's sidekicks. Her powers are not shown, as she's only seen driving a van. In the comic, she is summoned by Savvy alongside the rest of Savvy's deck to help him and One-Eyed Jack defeat the gas monster. After they defeat it, they prepare to fight against a garbage monster.
In "Pulp Friction", she is only seen driving the van, and her abilities aren't shown.
Lori's Korean dubber, MinJeong RYeo, also voices Mrs. Johnson. She also voices Marinette Dupain-Cheng for the Korean dub of "Miraculous: Tales of Ladybug and Cat Noir".
Lori is the only one of the Loud siblings who:
Has a driver's license.
Can keep the house from ending up in a pile of rubble or ashes.
Was born in the 1990's.
Is an excellent golfer.
Locks the door to her room on key.
Lori says that her favorite food is sushi, although she has never tried it.
Her dream job is to be the chief executive officer (more commonly called "CEO") of a major corporation--or, at the very least, the co-CEO of a major corporation.
According to the image of her feeding Lincoln ice cream in "The Whole Picture", she had an extra pair of eyelashes when she was younger.
According to The Loud House Instagram, her biggest pet peeve is people claiming that she's gassy. This was proven in "Making the Case". Also, as shown in both the episode, and the image where she was asked with the question, she tries to prove that it was her shoes that made the farting noise.
Lori was the first character to have her name in an episode title, before Lincoln and Lynn.
According to "Butterfly Effect", Lincoln apparently thinks that Lori secretly fears that Bobby might end up leaving her for their sister, Leni.