Mei is a 17-year-old college freshman studying biology at the Massachusetts Institute of Technology. Secretly passionate about dance, she struggles with a severe fear of germs that makes her chosen premedical path incredibly difficult. As a second-generation Taiwanese American, she feels caught between the rigid expectations of her traditional parents and her own desires for an independent college life.

Mama Lu is a Taiwanese immigrant who dropped out of graduate school to raise her children. She strictly adheres to traditional Chinese cultural values and expectations, frequently criticizing Mei to push her toward a successful medical career and an approved marriage. Despite her overbearing and prejudiced exterior, she harbors deep anxieties about her own life choices and genuinely desires security for her daughter.

Mr. Lu is Mei's father, a traditional Taiwanese man who prioritizes academic success, filial piety, and passing on the family name. While he was affectionate toward Mei during her childhood, he has grown stoic and demanding as she enters adulthood. He strictly enforces the family's estrangement from his son and uses it as a warning to keep Mei focused on her medical studies.

Darren is a biology student at MIT who hopes to eventually work in academia. As a third-generation Japanese American, he feels relatively disconnected from his ancestral culture but understands the pressure of family expectations. He is confident, kind, and observant, showing genuine interest in Mei's well-being and helping her experience the lighter side of campus life.

Xing is Mei's older brother and a successful doctor. As the eldest son, he faced immense pressure to uphold the family legacy but ultimately rebelled against his parents' traditional demands. His choice to prioritize his fiancée over his parents' approval led to his complete disownment, serving as a constant, fearful reminder to Mei of the consequences of disobedience.

Nicolette is Mei's second roommate at MIT. Initially presenting herself as cold and uninterested in friendship, she is actually trying to shed her shy high school persona by projecting confidence. As they spend more time together, she becomes a supportive presence who encourages Mei to take risks and enjoy college life.

Dr. Chang is a young Asian gynecologist working at the MIT medical center. She initially appears aloof, subservient, and somewhat unenthusiastic about her career, which she pursues primarily for financial stability. She shares Mei's intense fear of germs and bacteria, providing Mei with a confusing example of what her future in medicine might look like.

Esther is Xing's Taiwanese fiancée. She has a medical condition that affects her ability to conceive children, making her an unacceptable match in the eyes of Xing's traditional family. She feels immense guilt for being the catalyst of Xing's disownment but clearly shares a deep, loving bond with him.

Christine is a young woman whose past rebellion against her parents turned her into a neighborhood legend. Rather than failing as the community rumors suggest, she works as a confident comedian and uses humor to process the strict cultural traditions of her upbringing.

Nainai is Mei's paternal grandmother and the highly respected matriarch of the Lu family. She enforces the most extreme, outdated versions of traditional Chinese family values, demanding absolute obedience and prioritizing male heirs above all else. She struggles with dementia, which occasionally causes her to confuse the present with the past.

Aunt Yilong is Mr. Lu's sister. She acts as an enforcer of Nainai's strict traditional values and frequently echoes the older woman's harsh criticisms of Mama Lu and Mei. She expects complete submission from the younger generation and is quick to declare dramatic consequences for disobedience.

Helen is Mei's childhood friend who now attends Dartmouth. As a fellow Taiwanese American, she provides a contrasting experience to Mei's, as her parents are significantly less overbearing. She navigates college life and her cultural identity with an ease that makes Mei both jealous and curious.

Mrs. Pan is an acquaintance of the Lu family who frequently attempts to set up marriages within their community. She is highly focused on physical appearances and social status, acting as a representative of the community's traditional, gossip-heavy social network.

Leslie is a Taiwanese student who was Mei's original college roommate. She held deep prejudices against Mei's family due to their historical flight from China to Taiwan, viewing Mei's ancestors as invaders. This political tension quickly soured their living arrangement.

Eugene is a senior premedical student at Harvard. Because of his academic prestige and Taiwanese background, Mama Lu considers him the perfect future husband for Mei. In person, he is arrogant and primarily concerned with his own social standing.

Jenn is an MIT student whom Mei meets while traveling. She shares that her parents disowned her after she came out as a lesbian. Hearing her story helps Mei realize that parental judgment is not always absolute or correct.

Valerie is a student living in Mei's dorm who assumes Mei had a stereotypically restrictive childhood. She later appears at the medical center as one of Dr. Chang's patients, inadvertently worsening Mei's fear of the medical profession.

Mrs. Wong is Esther's mother. While she holds her own traditional views regarding marriage and childbirth practices, she is significantly more accepting of Xing than his own parents are of Esther, providing Mei with a different model of Taiwanese parenting.