Estrella is a 13-year-old Chicana migrant worker who labors in California's agricultural fields. Having worked since she was four, she takes on heavy responsibilities, including caring for her four younger siblings. She possesses natural strength and resourcefulness. She uses physical immediacy and a growing confidence in her own capabilities to handle her family's precarious existence.

Petra is Estrella's 35-year-old mother. She is prematurely aged by the physical demands of fieldwork and multiple pregnancies. Suffering from painful varicose veins, she relies heavily on her Christian faith and cautious pragmatism to keep her family intact. She loves her children fiercely but fears for their futures, particularly as Estrella enters womanhood.

Perfecto is a handyman in his seventies. He acts as a surrogate father to Petra's children. He offers a sense of stability through his ability to fix things and barter for goods, such as repairing a store's toilet for groceries. However, he secretly harbors deep homesickness. He frequently thinks about his past life and family in a distant canyon, causing him to reconsider his commitment to Petra.

Alejo is a 16-year-old migrant worker from Texas. He picks grapes and peaches alongside his cousin to fund his high school education. Unlike many other workers, he holds onto the dream of leaving the fields to become a geologist. He finds fascination in the prehistoric origins of oil and tar pits. He develops a quick infatuation with Estrella.

Gumecindo is Alejo's 15-year-old cousin. He works alongside him in the California orchards picking crops and occasionally stealing fruit to survive. He is less mature and more fearful than Alejo. He complains about the grueling labor and expresses deep anxiety about being out after dark, relying entirely on his older cousin for protection during their shifts.

Ricky is Estrella's 10-year-old brother and one of Petra's sons. He works in the fields alongside his family but struggles to handle the severe California heat. He often needs his older sister to scold him into wearing his hat to prevent dehydration. He holds onto childhood dreams, such as hoping to become a pilot someday.

Arnulfo is one of Estrella's younger brothers and Petra's sons. Like his siblings, he experiences the hardships of constant relocation and life in the labor camps. He frequently follows his brother Ricky's lead and depends on Estrella and Petra for guidance during their daily tasks.

Perla is one of Petra's youngest daughters and Cookie's twin sister. Too young to work in the fields or handle heavy chores, she relies entirely on the care of her mother and older sister Estrella. She observes the family's struggles from a position of relative innocence.

Cookie is Perla's twin sister and one of Petra's youngest children. Shielded from the harshest realities of migrant labor by her youth, she looks up to Estrella with a sense of awe. She views her older sister as a powerful, almost magical protector.

Maxine is a white girl who lived in the same labor camp Estrella's family recently vacated. She is illiterate and prone to aggressive behavior. She initially bonds with Estrella when Estrella reads magazines aloud to her. Their brief connection fractures after Maxine asks intrusive questions about Petra and Perfecto, prompting Estrella's family to move away to avoid Maxine's volatile family.

The unnamed clinic nurse provides medical examinations for the local migrant population. She appears strikingly clean against the rundown, improvised backdrop of the rural clinic. She operates strictly by clinic policy. She refuses to accept trade or barter for her services and demands cash payment simply to diagnose patients and refer them elsewhere.

Estrella's biological father abandoned the family when the twins were infants. He never appears in the present timeline, but his departure serves as a defining trauma for Petra. Estrella remembers him for his physical capabilities, specifically his ability to peel an orange in one continuous strip.

Mercedes is Perfecto's former lover from forty years ago. Having passed away from cancer, she lives on vividly in Perfecto's memories. She represents his deep longing for his past life, calling out to him in his dreams and pulling his attention away from his current responsibilities.