Alma is an elderly, wealthy artist and designer residing at Lark House in California. Born in Poland to a Jewish family, she was sent to live with her aunt and uncle in San Francisco just before the outbreak of World War II. She maintains a guarded, self-reliant exterior, dedicating herself to her art and philanthropy while harboring deep memories of her past and a lifelong connection to her childhood friend, Ichimei. She fiercely protects her independence and fears the physical decline associated with aging.

Irina is a 23-year-old Moldovan immigrant working as a care assistant for elderly residents. Raised by her grandparents before moving to the United States, she leads a quiet, frugal life and avoids close physical or emotional intimacy. Her patience and genuine respect for the residents quickly earn her an excellent reputation, eventually pulling her into Alma Belasco's personal orbit as an assistant and confidant.

Ichimei is a nisei (second-generation Japanese American) who grows up as the son of the Belasco family's gardener. He bonds instantly with Alma when she arrives from Poland, sharing a childhood friendship that evolves into a profound, lifelong connection. His life is deeply impacted by the forced incarceration of Japanese Americans during World War II, which shapes his quiet endurance, his connection to his heritage, and his artistic pursuits.

Nathaniel is the wealthy, philanthropic heir to the Belasco family and Alma's older cousin, who later becomes her husband. As a boy, he struggles to fit in at his elite secondary school and forms a close bond with both Alma and Ichimei. Despite marrying Alma, their relationship functions more like a supportive friendship, and Nathaniel harbors private truths about his own identity in a society that demands conformity.

Seth is Alma's 32-year-old grandson and the expected heir to lead the Belasco Foundation. Though he holds a law degree, he lacks genuine enthusiasm for the profession, preferring to ride motorcycles and write a book about his family's history. He becomes infatuated with Irina and tries to win her affection while helping uncover his grandmother's secretive past.

Isaac is the wealthy patriarch of the Belasco family. He manages multiple charity organizations and investments, successfully maintaining his fortune through the Great Depression. He is a benevolent and protective figure who formally adopts Alma and attempts to shield his Japanese American gardener, Takao, from the systemic prejudice that sweeps the country in the 1940s.

Takao is an issei (first-generation Japanese immigrant) who left a militaristic family in Japan to pursue cultural freedom in the United States. He applies his discipline to creating a diverse botanical garden for Isaac Belasco. The outbreak of World War II and the ensuing incarceration in heavily guarded camps severely test his resilience, stripping him of his livelihood and pride.

Lillian is Isaac's wife and the matriarch of the Belasco family in San Francisco. She oversees the daily operations of the Sea Cliff household and works to integrate her niece Alma into American society, though she often struggles to understand the young girl's quiet distress.

Lenny is an 80-year-old retired dentist whose arrival at Lark House turns heads due to his good looks and energetic attitude. He shares a deep, prior connection with Alma and Nathaniel from decades earlier, sparking curiosity among Alma's inner circle about the exact nature of their past relationship.

Heideko is Takao's wife, having immigrated to San Francisco for their arranged marriage. During their family's internment at the Tanforan racetrack and later Topaz, she takes a leading role in organizing and supporting the detained community.

Frenchie is a 90-year-old resident at Lark House, widely considered the facility's most desirable bachelor. He becomes intensely infatuated with Irina's youth, sending her letters and attempting to leave her his inheritance.

At 68, Cathy is the youngest resident at Lark House. She operates an informal clinic dispensing alternative medical advice and cannabis, and she acts as a supportive friend to both the staff and residents.

Megumi is Ichimei's older sister. During her family's incarceration at Topaz, she studies nursing and becomes a dedicated medical worker, attracting the attention of a camp guard while trying to further her medical ambitions.

Larry is the son of Alma and Nathaniel Belasco. Raised largely by his grandparents due to his parents' distant marriage, he grows into a mild-mannered man who relies heavily on his wife, Doris, to manage their household.

Samuel is Alma's older brother. When the threat of war looms over Europe, their parents send him to London for safety while Alma is sent to America, leaving the siblings separated by conflict and massive geographical distance.

Radmila is Irina's mother. She leaves Moldova for the United States in search of a better life, eventually bringing her young daughter to live with her and her new husband in Texas, setting the stage for Irina's difficult adolescence.

Hans is the director of the Lark House retirement community. He strictly enforces the facility's rules regarding gifts and inheritances but recognizes good work when he sees it, eventually promoting Irina.