Hannah Hartford is a central figure characterized by her intelligence and desire for independence, challenging the social norms of aristocratic women of her era. Her relationship with her sister Emmeline and love for Robbie Hunter are significant to the plot.

Emmeline Hartford is Hannah's younger sister, initially portrayed as charming and naive. Her character development reveals emotional complexity and involvement in pivotal events of the story.

Robbie Hunter is a charismatic poet whose relationships with Hannah and Emmeline create tension within the story. As an outsider, he represents the intrusion of new ideas and emotional depth at Riverton.

Teddy Luxton is Hannah Hartford's husband, exemplifying the changing upper class with his focus on business and social status. His marriage to Hannah is pragmatic, highlighting his conventional nature.

Frederick Hartford is the father of Hannah, Emmeline, and David, embodying rebelliousness and failed ambition in the early 20th century aristocracy. His role connects with the novel's central secret regarding Grace’s parentage.

David Hartford, the older brother of Hannah and Emmeline, is pivotal in connecting Robbie Hunter to the family. As the male heir, his presence contrasts with the lives of his more restricted sisters before his death in World War I.

Alfred Steeple is a footman and Grace's love interest, offering her a potential escape from domestic service. He later plans to establish an independent life with Grace, highlighting a romantic subplot.

The Riverton staff, including Mr. Hamilton, Mrs. Townsend, Nancy, and Katie, illustrate the hierarchical nature of early 20th-century domestic service. They provide a rich backdrop to the novel’s exploration of social class dynamics.