Lynn Loud was born on April 9, 2003, as the fifth child of Rita Loud and Lynn Loud Sr., the latter whom she is named after. When she was a toddler, Lynn found a passion for sports and it remains her primary interest to this day. In 2015, Lynn met Lucas Nelson and they quickly fell in love with each other. As of 2016, Lynn currently attends Royal Woods Junior High School and she is in the seventh grade. Lynn's most annoying habits include turning everything into a sport, roughhousing, and play fighting with his sisters and brother.
Lynn is athletic and competitive. She loves to play sports and enjoys roughhousing with her siblings.
She enjoys playing every existing sport, including football, soccer, basketball, and baseball. She is also skilled in various forms of martial arts such as kickboxing, Mexican wrestling, and parkour. Lynn tends to turn everything into a sport and her siblings consider this to be her most annoying habit. She is also shown to be very competitive and strives to be "number one" on every sports team she plays on.
After Lola and Lori, she is the third most easily angered Loud sibling, and is the most prone to physical confrontations.
Despite her tomboyish attitude, she has no shame in using puppy eyes to get what she wants. She also gets very excited with all her siblings after finding out about romantic situations.
She appears to be superstitious. One such example of this is Lynn's belief that she shall never go the bathroom before a big game of roller derby, because she thinks it's bad luck. Another example of her superstitions include her belief Lincoln is bad luck when he comes to her game and she loses as a result.
Despite her age, she sometimes acts childish, as she rides on carts in the grocery store and she frequently participates in food fights with her family.
Lynn has thick brown hair pulled back into a short ponytail. She wears a red and white jersey with a red "1" on it, red-and-white shorts, and cleats with striped knee-high socks. She is slightly taller than Lincoln, and has freckles on her cheeks. Despite her age, her appearance makes it seem like she's a preteen, not a teenager.
Her night-time attire consists of a white tank top, red shorts, and ankle high socks. In a few instances, she is shown wearing a nightshirt that looks like her regular jersey, with socks instead of her usual sleepwear. Her swimwear is a red-and-white surf shirt with matching swim trunks.
- Lynn in this series is voiced by Ashleigh Ball, unlike in The Loud House where she is voiced by Jessica DiCicco.
- Lynn is left-handed.
- Lynn has a widow peak hairline.
- Lynn is the most masculine and tomboyish of the ten Loud sisters.
- Lynn's biggest pet peeve is when Lisa spits while she speaks.
- Lynn's favorite movie is the 1996 sports comedy Jerry Maguire.