Annie is Mae's close friend who secures Mae a job at The Circle. She is driven and supportive but struggles with competition as Mae climbs the corporate ladder.

Mercer is Mae’s ex-boyfriend who lives in their hometown and serves as a prominent critic of The Circle's influence. His relationship with Mae provides a counterpoint to her immersion in The Circle's culture.

Mae’s parents are significant to her early motivations, as their well-being is a top priority for Mae, especially concerning her father's illness. Their experience with The Circle's intrusion exposes the tension between private life and public transparency.

Ty is one of the founders of The Circle, known as Kalden when interacting under an alias. He serves as a complex figure who expresses concern over The Circle's direction.

Bailey is a charismatic and visible leader among The Circle's Wise Men. He is known for his approachable demeanor yet is influential in pursuing The Circle's objectives.

Stenton is a leader among The Circle’s Wise Men, characterized by his aggressive pursuit of power and control. His stern approach contrasts with his partners in leadership.

Francis works at The Circle focusing on technologies to prevent child abductions. He becomes romantically involved with Mae, although their relationship lacks depth.