Paige Swanson is first introduced in Dr. John Sturgis's class as another 10 year old genius. She later appears at a lecture at a museum and dares Sheldon to sneak out and climb into a closed exhibit.
Paige first appeared in "A Rival Prodigy and Sir Isaac Neutron" during another of Sheldon's classes with Dr. Sturgis. She is smarter than him, causing him to be jealous, especially when Dr. Sturgis praises her too much in front of Sheldon. Mary invites Paige and her family over for a play date, much to Sheldon's chagrin.
Paige reappears in "Carbon Dating and a Stuffed Raccoon" when she goes to attend a lecture on carbon dating at a museum, which Sheldon is also attending. A little into the lecture, they both become bored by it and wander into a closed area of the museum. In there, Paige tells Sheldon about her parents probably getting a divorce because them fighting all the time. They are then caught by a security guard who then calls in the children's fathers, followed by Paige's mother.
Paige reappears in "A Stunted Childhood and a Can of Fancy Mixed Nuts" when she and her mother in the mall and they meet Sheldon, Mary and Missy at the shoe store. Missy and Paige go off to the Hello Kitty store at Medford's shopping mall where it is revealed that they had a good conversation together. Missy and Paige have a sleepover, during which Paige warns Sheldon that his excessively mature personality might cause him to be a social misfit and weirdo as an adult. Which she said is true and Sheldon did become a misfit and weirdo as an adult in The Big Bang Theory. During the stay, they play with Missy's dolls, tie Georgie's ankles to his bed so he'd trip and fall (which he eventually does the next morning) and Paige tells Missy an imagined scary story to which Sheldon is a pompous, annoying little brute about due to his lack of imagination.
In "Body Glitter and a Mall Safety Kit", Paige's parents, Barry and Linda, have gotten a divorce and it has negatively affected her appearance (she no longer wears dresses, but now wears denim outfits, has changed her hairstyle and has dyed a pink streak in her hair) and her attitude (she has become snarky, mouthy and rebellious, has turned to shoplifting and has grown indifferent to her schoolwork, resulting in her grades falling), so she goes to spend the weekend with the Coopers. Her devastation over her parents' divorce results in Sheldon learning to listen and he soon offers to make the distraught Paige a hot beverage, which he does when he heads to the kitchen to make her a cup of tea.
In "Bible Camp and a Chariot of Love" Paige returns, having been forced to go to bible camp with Sheldon. After refusing to engage Sheldon in competition, she punches Sheldon after he angers her by talking of her belief about her parents' divorce.
In "A Second Prodigy and the Hottest Tips for Pouty Lips." the President of East Texas Tech insists that Sheldon gives Paige a tour of the university, much to his chagrin. He agrees to do so, however, he secretly plans to sell it as an inferior school. Though she pretends to be looking forward to attending college with Sheldon in front of her mother, in reality she wants go to an out of state college a thousand miles away from her family like Harvard or Princeton. Meemaw and later Missy tries to convince Sheldon that he might have a crush on Paige. This turns out not to be true, because she decided to mess with him when she tried to kiss him and drew on a mustache on him to prove she hates Sheldon.
In "A Solo Peanut, a Social Butterfly and the Truth," Paige visits East Texas Tech as part of a lecture team from the University of Austin. Having no friends and living as an outsider at her own college, she decides to hide in Sheldon's dorm, believing that he can understand her position. But when she finds out he actually has friends, in the form of a group of older RPG nerds, she becomes frustrated and leaves. Later she returns and wants to drop out and transfer, but she wants Sheldon to keep her plan a secret. While seeking supplies for her from Missy, Sheldon reveals the reason for his actions, and tried to talk Missy into keeping the secret as well, but Missy told Mary. They decide to come to the dorm to help her. But Paige already fled, leaving a note for Sheldon. After some worrisome nights, they eventually learned she arrived home to try to deal with the issues with her mother,
- Paige is fluent in three languages.
- Like Sheldon, she shared a room with her sister.
- Paige is not fond of Professor Proton, much to Sheldon's fury.
- Unlike Sheldon's mother Mary and wife Amy, Paige would've called Sheldon out on his bad behavior.
- Ironically, Paige would engage in some bad behavior herself in "Body Glitter and a Mall Safety Kit" when she shoplifted a tube of body glitter from hot topic by sticking it into Sheldon's backpack.
- It is also revealed in "Bible Camp and a Chariot of Love" that she had started smoking and wearing lipstick to look older, due her parents going through a divorce.
- In "A Stunted Childhood and a Can of Fancy Mixed Nuts", after seeing Sheldon's homework, Paige reveals that she already learned it a year ago, which leads to the conclusion that she went to high school a year earlier before Sheldon, which would be at age 8.
- She and Sheldon are currently rivals. On the other hand, Paige is good friends with Missy as they have the same girly interests and get along without any tension. They also enjoy watching Sheldon get upset.
- Sheldon always thought of himself as a super genius and he usually has rivals who super genius like her and Dennis Kim.