Esther is a 19-year-old college student and aspiring writer who feels increasingly numb and alienated despite securing a prestigious summer internship. She is a high achiever from the Boston suburbs who struggles to figure out her identity and career path. A perfectionist by nature, she feels paralyzed by the pressure to choose between domesticity and her artistic ambitions. This overwhelming pressure triggers a severe bout of depression that fundamentally alters her perception of the world.

Buddy is a handsome, practical medical student who grew up in Esther's neighborhood. He presents himself as an ideal, virtuous partner but harbors hypocritical views regarding gender and sexuality. He views Esther's writing as a passing phase and fully expects her to abandon her ambitions to become a traditional wife and mother.

Mrs. Greenwood is Esther's widowed mother who works as a teacher to support her family following her husband's death. Highly practical and grounded in 1950s values, she wants her daughter to learn useful skills like shorthand to ensure financial stability. She struggles completely to comprehend Esther's artistic drive or the reality of her mental illness.

Joan is an academically talented, large-framed young woman who shares a similar background and social circle with Esther. Like Esther, she struggles with the pressures of early adulthood and experiences profound mental distress. She maintains an intense fascination with Esther's life and choices.

Doreen is a sharp-tongued intern from the South who provides a sharp contrast to the other girls in the program. She is sexually liberated and adventurous, preferring to skip mandatory internship events to drink and socialize with men. She acts as a subversive influence on Esther during their time in the city.

Betsy is a cheerful intern from the Midwest who embodies the all-American sweetheart archetype. She adheres perfectly to the behavioral expectations placed on young women of the era, eagerly attending banquets and fur shows. Her uncomplicated happiness makes Esther feel deeply inadequate.

Dr. Nolan is a young, progressive female psychiatrist who takes over Esther's treatment. Unlike previous doctors, she listens attentively, validates her patient's fears, and communicates treatment plans clearly. She represents a rare example of a successful, independent woman working in a male-dominated field.

Dr. Gordon is a conventionally handsome, self-satisfied psychiatrist who evaluates Esther early in her mental health crisis. He relies on outdated methods of diagnosis and shows more interest in the attractive women at Esther's college than in her actual symptoms.

Jay Cee is the formidable, career-driven supervising editor at Ladies' Day magazine. She commands immense respect due to her sharp intellect and professional success. She pushes Esther to develop practical skills to survive in the competitive publishing industry.

Philomena Guinea is a successful, established novelist whose financial patronage allows Esther to attend a prestigious college. She writes popular fiction that affords her a comfortable lifestyle, and she uses her resources to intervene when Esther faces a medical crisis.

Constantin is a simultaneous interpreter at the United Nations and a family connection of the Willards. He is intelligent, attractive, and cosmopolitan, presenting a sharp contrast to the men Esther usually encounters.

Lenny is a wealthy, boisterous disc jockey from New York who quickly courts Doreen. He is loud and aggressive in his playfulness, living in an apartment decorated like an extravagant bachelor pad.

Marco is a tall, intimidating man who harbors a deep-seated hatred for women. He is aggressive and demanding, using physical force and psychological manipulation to try and control Esther during their evening together.

Irwin is a tall, highly intelligent, and experienced man who invites Esther out for coffee. He is intellectually engaging but cavalier about his romantic entanglements, serving primarily as a mechanism for Esther to achieve a specific personal goal regarding her sexuality.