Ryō Shinnai holds the position of primary psychologist at Yū's Mental Clinic, maintaining a professional and doctor-like composure. His serious and grounded personality often casts him as the straight man in comedic scenarios. Childhood struggles with Irritable Bowel Syndrome directly fueled his pursuit of psychology, specifically aiming to treat psychosomatic conditions. His upbringing occurred in Africa, a distinct background from conventional settings.

His family environment saturated him in psychology, with nearly every member working in the field. Routine interactions, including dinner conversations, frequently turned into psychoanalytic sessions, compelling him to stay silent during meals to evade analysis. This habit reinforced his reserved disposition. His surname "Shinnai" combines the characters for "heart/mind" and "inside," while his given name "Ryō" signifies "heal" or "cure," reflecting his dedication to mending internal psychological wounds.

At work, he calmly explains mental health topics, consistently counterbalancing the chaotic antics of colleagues like Asuna Kangoshi and her sisters. His mother, Sakura Ryō, designed the clinic's uniforms, marking her influence on his professional space. He primarily functions as the clinic's educator, methodically delivering factual information on mental disorders despite relentless interruptions and absurd distractions from fellow staff.