Ji-won is a college freshman living in Koreatown, Los Angeles, with her mother and younger sister. She struggles with academic probation after her grades slip during her first quarter at the university. Following her father's abrupt departure, she observes her mother's erratic behavior and develops a growing fixation on blue eyes. She harbors guilt and defensiveness over alienating her high school friends before leaving for college.

Umma is a Korean immigrant who works at a local grocery store. Following her husband's sudden departure, she adopts extreme coping mechanisms, beginning with the consumption of whole fish eyes for luck. She carries trauma from severe childhood poverty and abandonment in 1970s South Korea. She aggressively pursues a relationship with a white man, believing articles that claim they make superior partners.

George is a middle-aged white man who meets Umma at the Korean grocery store where she works. He drives a truck with a Republican bumper sticker and carries a wallet stuffed with hundred-dollar bills. He refuses to pronounce Korean names correctly, substituting initials instead. He frequently overstays his welcome at Umma's apartment and makes the daughters uncomfortable with his open, predatory staring.

Geoffrey is a college student in Ji-won's philosophy and psychology classes. He initially presents himself as a progressive ally. He quickly inserts himself into Ji-won's daily routine, demanding her phone number and constantly texting her. He reacts with hostility when his attention is not reciprocated or when he feels threatened by Ji-won's other friendships.

Ji-hyun is a high school student and Ji-won's younger sister. She shares a bedroom with Ji-won in their small Los Angeles apartment. She frequently attempts to bridge the emotional distance her sister creates, expressing open anxiety about their family's instability. She is the first to confront Umma about her secretive phone calls and apparent dating life.

Appa is Ji-won and Ji-hyun's father, who grew up in extreme poverty in Busan before educating himself and attending Seoul National University. He moved to California seeking better opportunities but experienced severe financial setbacks. After years of complaining about his life and expressing disappointment at having daughters rather than sons, he abruptly leaves his family for another woman.

Alexis is a student in Ji-won's college classes who shares an off-campus apartment with a roommate. She provides Ji-won with practical support, including sharing notes, inviting her to study groups, and giving her sleeping medication. She serves as a calming presence in Ji-won's chaotic college life.

Jenny is one of Ji-won's former high school friends who now attends the University of California, Berkeley. She is the person who eventually pieced together the truth about Ji-won's manipulative behavior during their senior year. She organizes a coffee shop meeting to confront Ji-won about the past.

Sarah is a former high school friend of Ji-won who successfully gained admission to Berkeley. During their senior year, Ji-won framed her for stealing a valuable piece of jewelry. She attends the coffee shop reunion with Jenny and Han-byeol to hold Ji-won accountable for her actions.

Han-byeol is a member of Ji-won's former high school friend group. Her most prized possession, a ring passed down from her grandmother, was stolen by Ji-won and planted in Sarah's desk to destroy the group's trust. She now attends Berkeley with Jenny and Sarah.

Ha-joon is Umma's eldest sibling who features in her stories about growing up in 1970s South Korea. When their parents left to find work during a famine, he was placed in charge of the younger children. He squandered the money left for them and eventually abandoned Umma to follow their parents.

Min-ho is an old friend of Appa. He invited Appa to invest in a new business venture shortly after Appa bought a dry-cleaning business in California. He ultimately stole the investment money to pay off gambling debts, causing severe financial ruin for Appa's family.

Professor Thompson teaches psychology at Ji-won's university. He notices Ji-won's deteriorating condition and distracted behavior in class. He approaches her after an exam to suggest she visit the on-campus therapists.

Jen is a woman who maintains a relationship with George outside of his engagement to Umma. She kicks him out of their shared space, prompting him to move in with Umma.