Shawn's estranged father and a Pulitzer-Prize-winning author, who struggles with the emotional impact of Shawn's condition. His uncertainty about how to help Shawn and his own feelings of guilt and entrapment are central to his character.

A peripheral yet impactful character known for being charged with the death of his son, who had similar medical conditions to Shawn. He serves as a point of tension and reflection for other characters, especially Sydney.

Shawn's sixteen-year-old brother, known for his athleticism and rebellious nature. He has a volatile relationship with their father and exhibits a protective, albeit aggressive, love for Shawn.

Shawn's devoted mother, who exemplifies patience and unwavering support for her son. She maintains the family dynamic and cares deeply for Shawn, ensuring his emotional well-being.

Shawn's seventeen-year-old sister, who is compassionate and takes on a teaching role for Shawn. She is involved in mediating family conflicts and plays a supportive role in Shawn's life.