Sunja is the central figure of the family, a resilient and pragmatic woman who learns early on how to survive in harsh conditions. After an unexpected pregnancy threatens to ruin her family's reputation, she accepts a marriage proposal from a sickly minister and relocates to Japan. In Osaka, she quickly adapts to life as an immigrant, leveraging her work ethic to keep her loved ones fed by making and selling kimchi in the market.

Yangjin is the hardworking, practical mother of Sunja. She takes over the daily operations of her family's boardinghouse in Yeongdo after her husband passes away. Accustomed to a life of labor and self-denial, she focuses entirely on keeping her lodgers fed and her daughter safe during difficult economic times, carefully managing meager resources.

Hansu is a wealthy, well-dressed fish broker with ties to organized crime. Born into poverty, he claws his way to a position of power and views the world through a strictly practical, unsentimental lens. He takes a strong interest in Sunja, offering her glimpses of a wider world while operating under his own rigid code of self-interest and authority.

Isak is a gentle, idealistic Presbyterian minister traveling from Pyongyang to Japan. Having suffered from poor health his entire life, he possesses a deep empathy for the suffering of others and seeks a way to make his fragile life meaningful. He offers to marry Sunja to save her from social ruin, providing her unborn child with a name and a legitimate family.

Noa is a quiet, studious boy who idolizes Isak and loves reading. Growing up in a marginalized Korean community in Japan, he intensely desires to be accepted by mainstream society and works tirelessly at his education. He prefers formal learning to the rough-and-tumble world of his peers, hoping to earn a respectable desk job and overcome the stereotypes associated with his heritage.

Mozasu contrasts sharply with his older brother, possessing boundless energy and a strong distaste for formal schooling. He responds to the discrimination he faces by fighting back, eventually dropping out to work in the local pachinko parlors. Once employed, he channels his fighting spirit into an exceptional work ethic and quickly proves his value to his bosses, achieving significant financial success.

Solomon represents the younger generation of the family, raised with the privileges his father and grandmother fought to secure. Educated in international schools and later in the United States, he develops a pragmatic, cosmopolitan worldview. He maintains a close bond with his father and grandmother while dealing with the realities of living in a country that still legally classifies him as an alien resident.

Hoonie is Sunja's father, a mild-mannered and hardworking man born with a cleft palate and a twisted foot. Despite his physical challenges, he possesses great strength and provides for his family by running a seaside boardinghouse. He dotes on Sunja, teaching her the value of hard work, kindness, and self-respect.

Yoseb is Isak's older brother, a factory worker living in the Korean ghetto of Osaka. He holds traditional views regarding gender roles and family hierarchy, initially insisting that his wife and sister-in-law stay out of the workforce. He carries a heavy burden of responsibility, constantly worrying about money and the safety of his gentle younger brother in a hostile country.

Kyunghee is Yoseb's beautiful, kind-hearted wife. Unable to have children of her own, she immediately treats Sunja like a younger sister and dotes on Sunja's children. She maintains an impeccably clean home despite their impoverished surroundings and carefully manages the family's meager finances under Yoseb's traditional rules.

Yumi is a young seamstress who catches Mozasu's attention. Driven by a desire to escape her difficult childhood and the pervasive discrimination in Japan, she studies English diligently at a local church. She dreams of moving to America and building a completely new life far from her parents' history of poverty and crime.

Etsuko is a Japanese restaurant owner and Mozasu's girlfriend. Having endured a difficult divorce that left her estranged from her own children, she finds comfort in her relationship with Mozasu and his extended family. She acts as a maternal figure to Solomon while nursing quiet guilt over her fractured relationship with her daughter.

Hana is Etsuko's rebellious, independent daughter. Deeply affected by the fallout of her parents' divorce, she acts out against authority and struggles with feelings of worthlessness. She develops an intense, complicated bond with Solomon, frequently warning him about the harsh realities of Japanese society and refusing to conform to expectations.

Kim Changho manages a yakiniku restaurant in Osaka. Impressed by Sunja's cooking skills, he offers her and Kyunghee lucrative kitchen jobs, providing the family with a crucial financial lifeline during difficult economic times. He harbors idealistic hopes of eventually returning to a rebuilt Korea.

Goro is a pachinko parlor owner who provides Mozasu with his first job in the gambling industry. He recognizes Mozasu's raw potential, loyalty, and work ethic, eventually promoting him to manage his most important locations and serving as a key mentor.

Haruki is a quiet boy who becomes Mozasu's lifelong friend after Mozasu defends him from bullies at school. He eventually joins the police academy and marries, but he harbors secret feelings for men, hiding his true identity behind a conventional lifestyle to survive in Japanese society.

Phoebe is Solomon's Korean-American girlfriend. Having grown up in a diverse environment in the United States, she is completely shocked and outraged by the systemic discrimination Koreans face in Japan. She struggles to understand why Solomon accepts his alien status and urges him to return to America.

Kazu is Solomon's Japanese boss at an international investment bank. Educated in Texas and California, he projects a pragmatic, fraternity-brother persona and respects Solomon's exceptional business acumen. Despite his Americanized attitude, he remains bound by the strict corporate and societal expectations of Japan.