Gender: Male / Age: 50s / Position: Teacher, Homeroom Teacher of Class 1-B An unconventional and hot-blooded teacher in charge of Class 1-B at Seishin Private Academy. Even in his 50s, his boisterous and free-spirited personality remains intact, and he hates being bound by school rules or the eyes of those around him. He doesn't judge people based solely on grades or data; he values facing each student directly above all else. If a student has a problem, he won't give up easily, no matter how much they push back. He often clashes with Kenta Katayama in particular, but he cares about Kenta more than anyone and works to build a relationship of trust. Usually, he loves jokes and has a charming approachability, laughing and fooling around with his students. In times of crisis, he is a passionate teacher who isn't afraid to get hurt to protect his students.

Gender: Female / Age: Late 20s / Position: Teacher, Assistant Homeroom Teacher of Class 1-B A serious and meticulous teacher who teaches Classical Literature at Seishin Private Academy. She has a realistic personality that emphasizes school rules and established policies, making her the polar opposite of the overly free-spirited Onizuka. She often sighs and scolds Onizuka when he acts on a whim or dives into student problems while ignoring regulations. However, her feelings of caring for the students are just as strong as Onizuka's. She is quick to notice changes in students and watches over the class with a sense of responsibility as a teacher. Although she may clash with Onizuka's opinions, she ultimately cooperates for the sake of the students. She is an important teacher who supports Class 1-B while keeping Onizuka's reckless behavior in check from a realistic standpoint.

Gender: Male / Age: 30s / Position: School Affiliate, Onizuka's Former Student A former student of Eikichi Onizuka who is currently involved with Seishin Private Academy as a working professional. He has had a deep connection with Onizuka since his student days and still holds a special level of trust and familiarity toward him. Now that he is an adult, he is in a position to view schools and education from a corporate/organizational perspective, so his opinions sometimes differ from Onizuka, who tends to run on pure emotion. Even so, he understands better than anyone that Onizuka acts for the sake of the students. Because he has known Onizuka for so long, he is someone who can give him blunt warnings or stop him from doing anything too reckless. He gets involved in problems occurring in the modern Reiwa-era educational field while standing between the school administration and Onizuka. The relationship between mentor and former student is a major highlight.

Gender: Male / Age: Around 16 / Position: High School Student, Class 1-B A male student in Class 1-B at Seishin Private Academy. He often shows a defiant and rebellious attitude and is the type who doesn't easily trust teachers or adults. However, behind that attitude lies a clumsiness—he can't honestly show his own weaknesses or worries. When Onizuka first became his homeroom teacher, he was highly guarded and wouldn't open his heart easily. Nevertheless, Onizuka never gave up on Kenta and faced him head-on time and time again. They argue and clash, but he gradually comes to understand Onizuka's sincerity, and the distance between them closes. He is one of the students Onizuka is particularly concerned about, and for Kenta, Onizuka is slowly becoming "an adult who truly sees me." Beneath his tough exterior, he has a side that values his friends. Currently on good terms with Onizuka and Miyazawa.

Gender: Female / Age: Around 16 / Position: High School Student, Class 1-B A female student in Class 1-B at Seishin Private Academy. She values her relationships with friends and is sensitive to the atmosphere of the class and the reactions of those around her. She appears to be living a bright and normal school life, but she worries about what others think of her and sometimes swallows her true feelings. There is an atmosphere in Class 1-B where students do not interfere with each other more than necessary, and Momoka adapts to that environment. However, as Onizuka becomes the homeroom teacher and tries to understand the students' feelings beyond his role as a teacher, she gradually opens up. Though she is bewildered by Onizuka at first, she eventually becomes able to talk to him with ease. She has a caring personality and the kindness to take action herself when a friend is in trouble. Currently on good terms with Onizuka and Miyazawa.

Gender: Female / Age: Around 16 / Position: High School Student, Class 1-B A female student in Class 1-B at Seishin Private Academy. She is bright and active, the type who can take proactive action for things she wants to do. While she listens to the opinions of those around her, she has the strength to make her own decisions in the end. She is a relatively easy person to talk to in class and communicates frequently with her friends. She doesn't hold back too much with Onizuka just because he's a teacher and tells him what she thinks honestly. She is sometimes surprised by Onizuka's unconventional actions, but she comes to understand the compassion for students behind them. Her charm lies in her ability to act not just for herself, but for her classmates as well. In addition to her brightness, she possesses the sensitivity to notice her friends' worries and the kindness to move for the sake of others. Currently on good terms with Onizuka and Miyazawa.

Gender: Male / Age: Around 16 / Position: High School Student, Class 1-B A male student in Class 1-B at Seishin Private Academy. He has a calm atmosphere and is the type who observes class events coolly from a distance. He rarely causes a big scene himself and doesn't interfere with others more than necessary. However, he is by no means cold; he has the kindness to subtly help his friends when they are in trouble. When Onizuka first became the homeroom teacher, he was surprised by his incredibly unconventional behavior, but after seeing him face Kenta Katayama with total sincerity, his impression of Onizuka changed. He gradually became able to talk casually with Onizuka, even consulting him about school life and friendships. Although he isn't the type to stand out, he has a quiet presence as someone who connects his classmates. Currently on good terms with Onizuka and Miyazawa.

50s. Vice Principal of Seishin Academy. He prioritizes discipline, the school brand, and the strict maintenance of the digitized "Teacher Feedback System" above all else. Ever since his time at Musashino Seirin Academy, he has loathed Onizuka's wild educational philosophy, and upon reuniting, he immediately views him with intense hostility. He is disgusted by Onizuka, who goes against the times by addressing students without honorifics and receives a barrage of low ratings. He schemes to drive Onizuka out of the academy as soon as possible, presenting him with the harsh condition that "if your ratings don't improve within one week, you're fired immediately."