Jo is a 17-year-old Chinese American girl living undocumented in 1890s Atlanta. She resides in a secret basement beneath a newspaper printing shop with her adoptive father, Old Gin. Frustrated by the strict racial and gender barriers around her, she secretly begins writing a progressive, witty advice column under the pseudonym "Miss Sweetie" to help save the struggling local paper.

Old Gin is an elderly Chinese man who works as a groomsman for the wealthy Payne family. He raised Jo as his own child, providing her with a classical education from his past as a schoolteacher in China. Though he appears frail and passive, he possesses a strong moral compass and engages in quiet protests against segregation.

Nathan is the 19-year-old son of the Focus newspaper's publishers. He works as a reporter for his family's struggling paper and hopes to increase readership with fresh ideas. He is idealistic and firmly opposes segregation, though his privileged upbringing sometimes shields him from its daily realities.

Noemi is a part-Portuguese, part-Black woman working at the Payne estate. She is fiercely determined to claim space in a segregated society, fighting for basic rights and autonomy. She actively challenges the white-dominated suffragist movement when they refuse to include women of color in their platform.

Mrs. Payne is a wealthy Southern woman who represents Atlanta's old money. She employs Old Gin at her stables and hires Jo to serve as a maid for her daughter, Caroline. She maintains immaculate comportment and strict adherence to social etiquette, trying to balance her societal obligations with the progressive shifts occurring in the city.

Billy is a notorious Atlanta fixer and criminal. Passing as white, he runs a brothel and uses intimidation to collect debts. He aggressively pursues Old Gin over a large sum of money, utilizing violence and leverage to force compliance.

Caroline is the spoiled daughter of the Payne family. Having recently returned from finishing school, she frequently bullies the household staff, including Jo and Noemi. She feels intense pressure to secure a husband and maintain her social standing, leading to deep personal insecurities and defensive cruelty.

Merritt is the son of the Payne family. He is engaged to a woman from Boston but continues to flirt inappropriately with Jo, a habit that previously cost Jo her employment at the estate. He enjoys riding his new Arabian horse and participating in high society events.

Mr. Payne is the wealthy patriarch of the Payne family. He provides the paper supply for the Focus newspaper, giving him considerable leverage over its publishers. He is highly protective of his family's reputation and strongly opposes the progressive views published in the "Miss Sweetie" column.

Mr. Bell runs the Focus, a progressive newspaper in Atlanta. He struggles to keep the publication afloat against a rival paper while maintaining its anti-segregation stance. He remains completely unaware that Jo and Old Gin live beneath his print shop.

Mrs. Bell manages the Focus alongside her husband. She loves language and actively seeks ways to boost the paper's circulation. Her family conversations, unknowingly overheard through a speaking tube, provide Jo with education and comfort in the basement below.

Mrs. English owns English's Millinery, where Jo initially works as an apprentice. She strictly enforces social hierarchies and dismisses Jo for acting above her perceived station, demonstrating the rigid expectations placed on young, non-white women in the workforce.

Lizzie is an apprentice at English's Millinery. As a white, middle-class girl, she is permitted to be as opinionated as Jo without facing the same professional consequences. She is a loyal friend to Jo and actively follows the advice printed in the "Miss Sweetie" column.

Robby is Noemi's husband. He works at Buxbaum's convenience store and occasionally as a cook for the Payne household. He places himself at immense personal risk to intervene when Billy Riggs harasses Jo in the store.

Miss Saltworth is a wealthy Atlanta socialite representing "new money." She frequents the millinery shop to purchase hats and closely monitors high society gossip. She is engaged to Mr. Quackenback but remains suspicious of his activities.

Mr. Quackenback (often referred to as Mr. Q.) is an affluent gentleman in Atlanta society. Though officially engaged to Miss Saltworth, he engages in clandestine meetings with Caroline Payne.

Shang is a mysterious former groom at the Payne stables. He fled Georgia years ago following a scandal involving a misunderstood relationship. A massive debt he left behind now threatens Old Gin's safety, forcing Old Gin to deal with dangerous criminals to recover a pawned heirloom.

Bear is Nathan Bell's affectionate sheepdog. Because he recognizes Jo's scent from her time living secretly under the Bell household, his enthusiastic greetings constantly threaten to expose her carefully maintained anonymity in public.

Sweet Potato is a mare kept at the Payne stables. Born with a slight physical disadvantage, she forms a strong bond with Jo, who frequently rides and cares for her under Old Gin's supervision.