She wears a yellow hoodie on top of her school uniform, along with blue knee socks and white trainers. She has light brown eyes and hair that is kept up in a ponytail with bangs pushed slightly to the right side. Her uniform consists of a white shirt, blue ribbon, and a dark blue skirt.
Sasha is simply fun-loving, trying to find enjoyment in each day at school. She has a tendency to be simple-minded or impulsive when making decisions and because of this people do not always take her seriously. Her addiction to food is extremely emphasized in the series as well.
Sasha carries a breakfast watermelon on her way to school, but it is destroyed when Eren Jaeger accidentally crashes into her. He apologizes by giving her a small picture of him. Angered, Sasha demands for him to pay for her watermelon. She runs to school and goes to class 1-4 with her classmates, but ends up in the Titan side of the school where she gets bombarded by giant stationery. She tumbles out the classroom, but is rescued by Hannes the janitor, who shows them to their actual classroom. Sasha later introduces herself while being caught eating a rice ball. She is punished by her homeroom teacher later on but is interrupted by the school announcement for first years. As a welcoming act by the Colossal Titan principal, he kicks down the Wall and Sasha's lunch is stolen.
Sasha wonders why the person sitting next to Eren has been absent for a long period of time. That turns out to be Armin Arlelt, who is properly introduced to her later. Sasha follows her friends to find the Attack Junior High Scout Regiment, where she is accepted into said unauthorized club. The next day, her name is signed up for the Wall Cleanup Club by Mr. Keith, who assigned them to a random club because they did not send in their admission forms.
Sasha is one of Jean's team members. While the game progresses, Armin catches her eating ramen in the middle of the ongoing game. Though her teammates underestimate her, Sasha dodges the balls single-handedly, however her technique is handicapped due to her inability to throw balls while holding food.
As a result of the Scout Regiment's unauthorization, Sasha is forced to clean the windows along with the group but instead of cleaning she writes "Potato" on the glass panes indicating her hunger. After Jean is being caught slacking off, Rico Brzenska introduces the omni-directional mobility gear to Sasha and the group. Along with everyone else, Sasha complies to finish their task in order to get tutored as to how to use the gear. By impressing the Wall Cleanup Club president with the windows' cleanliness, Rico fulfills her promise to Sasha along with the rest.
While Eren struggles with his gear, Sasha freely operates the gear with ease. Rico then dismisses the group upon finding out that Eren's gear is broken. The next day, Sasha and the rest are happy for Eren's success in using the gear. Within a sudden, Sasha feels a tremble on the ground, originating from an incoming bunch of Titans heading their way. Sasha is enraged to find out the real purpose of the Wall Cleanup Club.
The day of the test results, Sasha is scolded by Keith Sadies because of her failures. She begs Eren then Mikasa to stay and help her but they leave for the Scout Regiment activities. Sasha tells Jean she does not need his help then worries about who might help her and does not notice Bertholdt Hoover who was proposing his help. When she sees Armin, Sasha asks him if he could help her out and he agrees, proposing to help Conny as well. Later on, Armin and Sasha are on their own, Conny having forgotten the study sessions. They make some maths exercises. To help his classmate solving equations, Armin advises her to replace unknown values with food, which turned out successful.
They eventually walk home and Sasha notes Armin's kindness, despite finding him weak as well. They wave goodbye but soon after, Armin runs back to Sasha, crying and saying he was afraid of dark, which comforts Sasha in her portrayal of weak Armin. Sasha however fails at the makeup test due to being distracted by maths food metaphors.
Sasha is shocked after seeing Jean with a new hairstyle and finding out about a love letter he received. When Christa arrives with sweets for Sasha, she gratefully embraces her, before Ymir tries to get Sasha off Christa. Later, when Jean's love letter turns out to be from a Titan, Sasha tries to comfort him by giving him two fake girlfriends; a curry bun and a daikon radish.
Sasha runs in order to buy the last yakisoba bread, but Hange snatches it before she could, to her dismay. Arriving late at the Scouts club, the upperclassmen start nitpicking over the group, with Petra mentioning an embroidery on Sasha's socks. They are later grounded with cleaning chores. After Levi gives the group a challenge, Sasha participates in the school's Sports Day.
At the start line of the bun-eating race, She sprints ahead as the signal is fired, and as Sasha lunges at the yakisoba bread, Hange suddenly comes from behind riding a Titan and it lunges at the pole holding the buns, enraging Sasha. In the last game, shoulder wars, Sasha teams up with Mikasa, Mina, and Ymir.
The upperclassmen plan a sudden "Test of Courage" event at night. In the bathroom, Sasha, Ymir, and Christa hear one of the school's Seven Wonders, a ghost voice coming from one of the stalls after Ymir dares knocking it three times. They run out of the bathroom, and Ymir mistakenly carries Sasha instead of Christa. Sasha continues chasing after a crying Ymir, until she is reunited with Christa. They head to the gym with Eren's group, and everyone starts running around as ghosts and a giant cannon appear chasing after them. It is later revealed that the event is a prank played by the upperclassmen.
Sasha visits the summer festival with her friends, complimenting Annie wearing a kimono. She heads with Conny to buy shaved ice for the group and take too long, resulting in the ice melting. She later participates in die-cutting with her friends and watches as more festival fireworks are set into the sky.
After an election for a new student council president is held, Sasha asks Jean if he is running for it, and he confidently answers that he is. When the candidates start chasing after a notebook that allegedly contains info which could help them win the election, Sasha joins the pursuit. She intercepts Conny and Jean, momentarily stealing the notebook and taking a glimpse at what is inside, learning that the school gets more yakisoba bread on Wednesdays.
In the school's 104th festival, Sasha participates in a Snow White play as the huntsman, changing her line to a one about meat. Sasha later arrives at the chee-burgs stand and tells Eren and Mikasa to switch places with her at the play. Seeing them determined to sell their chee-burgs, Sasha commends their spirit and offers to help them. She later tries stuffing chee-burgs in her pockets, but Mikasa catches her.
Sasha joins Eren and the others in pursuing their stolen chee-burgs from the Titans' building. After being rescued by Hannes, he points them to the principal's office and in there, Eren opens up a door using a key. The Colossal Titan then lifts the roof and eats the chee-burgs stand along with Eren, but later spits him out and Eren reveals a chee-burg he retrieved, with Sasha celebrating their victory.
- Conny Springer - Sasha and Conny are often a comedy duo; together the two of them enjoy pulling pranks and making jokes. They have a lot of things in common, such as their enjoyment of fun at school, and their tendency to not study for tests.
- Armin Arlelt - Although a bit unsure of Sasha because of her eating habits at first, they become closer to one another when he helps her study for the makeup exams when she failed her first one. Sasha notes that her first impression of him was that he was weak, but now she sees him as very kind and smart, and he has a lot of wonderful traits. She then sees him as weak again after he runs back crying to her because he was scared of the dark. It is inferred that they became good friends after that, as they seemed to get a long with each other well.