Evelyn, known as Eve, is Katey's best friend and roommate from Indiana. Despite her wealthy background, she chooses to be independent in New York. Eve struggles with jealousy and anger, particularly in relation to Tinker Grey. Following a car accident, she faces physical challenges and significant changes in her life.

Tinker, also called Theodore or Teddy, is a charming banker who appears to come from a wealthy background. However, his history is marked by financial difficulties due to his father's actions. Tinker is linked to Anne Grandyn and faces moral and personal struggles throughout the story, including a significant incident that affects Eve.

Wallace is an old friend of Tinker’s, from a wealthy family but prefers a simpler lifestyle. He is sensible and kind, avoiding ostentation and enjoying personal connections. He and Katey develop a friendship after trying to understand their compatibility as more than friends.

Anne is a wealthy woman from old money who initially appears as Tinker's godmother but is later revealed as his lover. She is intelligent, confident, and accustomed to having her way, and serves as a foil to Katey.

Hank, or Henry, is Tinker's older brother and an artist living modestly. Although he is critical of Tinker's choices, he has a complex relationship with him, sometimes supporting and illuminating Tinker's character for Katey.