Look, you'll always be my bae. But you need to take this project as seriously as I take our forbidden love.
— Sarah to Max, The Girl with the Dragon Snafu
Sarah is the leader of a group of very smart students in Hiddenville High, comprising of Phoebe, Evan, Tyler and Ashley. Sarah's group usually works together for class projects and in competitions such as the Math Bowl. Despite being the leader of the group, Sarah often compromises the needs for her group whenever she gets an opportunity to be with Max because she has a giant crush on him.
Sarah is introduced as one of the Honors Math class students leading her friends to cheer for Phoebe while solving a math problem. When Max joins Phoebe's math class, Sarah instantly falls for Max. She's surprised that Phoebe didn't tell her that she had such a hot brother. When Phoebe is chosen to be the team captain for the Math Bowl team, Sarah promises to be on her team. However, she pretends to be sick and joins Max's team instead. She comes over to the Thundermans house to study with Max and when Phoebe confronts her about lying, she says she was sick - lovesick. Sarah and Evan go Max's Lair to study, making her the first non-supe to enter Max's Lair. She's intrigued by how smart Max is and fantasizes about how cute and smart their kids will be when they get married.
During the school dance, Sarah struggles to get a chance to dance with Max but Max keeps avoiding her. Courtney, Max's crush forces him to have dance-off with her boyfriend so that she can dance with Max instead. Max wins the dance-off and tells Courtney that she has to do a dance-off with Sarah in order to date him. This gives Max and Phoebe a chance to leave the dance. Sarah follows them and finds them at the Cole's. She starts chasing Max. Max freezes her with his Freeze Breath but Phoebe accidentally unfreezes her with her Heat Breath and shows Sarah the direction to which Max ran.
Sarah is one of Phoebe's friends invited for Phoebe's first sleepover. She is mostly excited to be there because of Max. When Max steals the 3D TV from the girls, Sarah is impressed by Max and calls him a trickster and a fun guy, which annoys Phoebe. Phoebe's sleepover gets boring and Sarah is willing to go to Ashley's sleepover as long as she has a cute brother like Max. Sarah is the first one to be levitated when Phoebe uses Telekinesis to convince the girls that the Light as a Feather game is working.
Sarah wants to get Max's paintings for the school art auction. Hank officially meets Sarah and realizes that she's the girl he's been trying to keep off his backyard (apparently for stalking Max). Sarah She sees Max's stolen painting of a beautiful girl and tells Max that she loves it. To discourage Sarah, Max draws a huge beard on the girl painting. Sarah concludes that Max likes girls with beards. So, she grabs a black marker pen and draws beard on herself. During the auction of the painting, Sarah vows to outbid everyone.
With pressure from Nora, Sarah competes with Barb to see who will buy the painting. Barb doesn't want to buy the painting because of the ugly painting while Sarah doesn't have enough money. So, they keep raising the price one-dollar at a time, buying enough time for Phoebe, Max and Billy to return from the Hiddenville Museum. When the price gets too high for Sarah, Nora suggests that Sarah could get a loan or use college fund to pay for Max's painting. But Sarah has a better idea: she grabs Max's painting and runs away with it.
Sarah's group wants to do their Chinese culture project together for Mrs. Austin's class but Max manipulates Phoebe into joining Winnie Lee's popular group instead. This makes Sarah angry at Phoebe for ditching them but she quickly becomes happy again after Max takes Phoebe's spot on Sarah's team. Evan and Tyler advise Sarah that working with Max is not a good idea but she doesn't listen to them because she keeps getting lost in Max's eyes. Sarah is offended that her teammates don't trust Max. Of course Max lets the group down by forgetting to take the paper mache dragon inside, causing it to be rained on. The following day, Sarah's teammates help her see the truth by taking off her glasses so that Max's handsomeness doesn't distract her. She confronts Max for ruining their projects but admits that she still loves him. Phoebe helps Sarah's team get another dragon and Sarah forgives her.
Ever since Max broke up with Allison in 21 Dump Street, Sarah starts to crush on Max again and won't leave him alone. She brings Max a little beehive in school, signifying she's "Max's honey", only to find out that there are still some bees in it. Later at home, the Thunder Twins find out that Sarah set up a tent on the porch of their house. Phoebe decides to set Gideon and Sarah up with each other so that way they’ll become a couple and that they’ll leave them alone. Sarah and Gideon arrive at Splatburger after receiving invitations from Phoebe and Max. Meanwhile, the Thunder Twins sit at the other side of the restaurant watching them, trying to make them fall for each other. When they plan to leave Splatburger after they thought the Thunder Twins stood them up, Max turns off the lights to stop them from leaving. When the lights were off, tripped in the dark just now but Gideon manages to catch her. They compliment each other and start to fall in love.
Eventually, Sarah goes to the movies with Gideon and both plan to go to Sarah's rock star uncle, Sugar Ray's, concert as their second date. That is when Max finds out that Mark McGrath (a.k.a. Sugar Ray) is Sarah's uncle and not the janitor at the school of the same name. After this realization, Max starts to think of ways to get Sarah to be in love with him again in order to meet her uncle and go on tour with him during the summer, achieving his dream of becoming a rock star. Eventually, Max's plans are foiled by Phoebe and after seeing how Gideon makes Sarah happy, Max decides to gives up and leave them alone.
Sarah is a smart, happy, sarcastic, cheerful, cute and kind girl. She also likes school and enjoy math.
- Max Thunderman - Sarah adored Max and had a major crush on him. From the episode Report Card she makes her feelings known. She fell in love with Max when she first saw him, in the episode Going Wonkers she wanted Max to dance with her at the school dance. She would do anything for Max even if it affects other things she cares about like her group. She's usually unable to think straight when Max is around.
- Phoebe Thunderman - She's good friends with Phoebe and they appear to get along very well.
- Evan - Evan is usually in Sarah's group and they're seen working together multiple times.
- Tyler - Tyler is also a friend of Sarah's and usually works together with Sarah.
- Gideon - Gideon is Sarah's boyfriend. They become a couple in the episode Can't Hardly Date when Max and Phoebe set up a fake double dinner date at Splatburger. Gideon and Sarah get tired of waiting for Max and Phoebe to show up and they start dating.
- She has a gigantic crush on Max and describes him as a "prime number."
- She's good at math.
- Her math bowl team name is "Trig Monkeys."
- She wears glasses.
- She and Phoebe are in the same art class.
- She was frozen by Max in the episode Going Wonkers.
- She's the first non-supe to enter Max's Lair.
- She returned in Can't Hardly Date, the first episode she appeared in since The Girl with the Dragon Snafu.
- She has a bloodhound named Watson, which she claims it never fails to track Max down.
- Sarah's dog Watson is named after Sherlock Holmes sidekick Watson.