Katsuragi Genjirou is a construction worker and a former student of Suzuran High. He was seen as a big brother figure to a few notable students at Suzuran, including the Ebizuka Trio and Rindaman. Known to willingly give students whatever information they need--as long as they have a cigarette or two to spare.
Katsuragi is considered one of the strongest men in Suzuran's history. His faction, the Katsuragi Faction, only consisted of 6 people, but was still one the feared factions that kept the power balance in check at Suzuran. During the great war between Suzuran and Housen, Katsuragi did not listen to seniors Kawaishi Noboru or Nakai and refused to be apart of the war. Katsuragi was also in the hospital with appendicitis. He heard about the aftermath of the war and the death of Housen's Makio Bitou from a friend.
Katsuragi took it upon himself to meet up with some Housen members and created the non-aggression pact between Suzuran and Housen. Suzuran doesn't go near Housen and Housen doesn't go near Suzuran's neighborhood.
In Katsuragi's senior year, Katsuragi tried to unite Suzuran but didn't succeed. He also becomes friends with Suzuran freshman, Rindaman and looks out for him. Once while walking back home, Katsuragi comes across Odajima and a few Suzuran students, and Ebizuka middle school students Makoto Sugihara, Toshiaki Honjou, Hiromi Kirishima and Iwashiro Gunji. When they all see Katsuragi walking towards them, the Suzuran students panic in fear. Katsuragi stops, asking whats going on and looks at the middle school students. After looking at them, Katsuragi turns to Odajima and says to him ''Odajima, what the fuck do you think you are doing fighting middle schoolers?!'' Odajima and the rest of the Suzuran students apologize and run in fear. Katsuragi tell the middle schoolers that there are a few students like that at Suzuran who give the school a bad name, but there are also students like them who cherish their friends. When Hiromi Kirishima enters Suzuran and Katsuragi has graduated, Kirishima often talks to Katsuragi outside of school for information or advice.
It is implied that Katsuragi had fought the 2nd generation of the Front of Armament and was victorious, but regrets not finishing off Kunou Hideomi, who would later become the head of the 3rd generation of the Front of Armament. While at Suzuran, many people copied his style and grew mustaches as they felt he was the strongest at Suzuran.
Katsuragi helps Yasuo Yasuda escape from the The Front of Armament by giving him a lift in his new car . However, one of the Fronts Four Kings, Iwai Masanari, chase them on motorbikes and force them off the road . Yasu is unharmed in the crash, but Katsuragi is unconscious and is sent to hospital.
When Rindaman finds out that Katsuragi is in hospital and Iwai is responsible, Rinda goes looking for him. When Rinda arrives after Harumichi Bouya beats Kunou Ryuushin, Rinda asks who is Iwai and says to him ''I owe you one for Katsuragi san'' and knocks him out .
Katsuragi also saves Rindamans life when Issei Kunou, Kunou Hideomi twin brother, tries to kill him by stabbing him behind his back. After the ordeal, Katsuragi meets up with the seniors of Suzuran and tells them the that The Front of Armament has been insulting Suzuran. Katsuragi's lie rallies the students and all of Suzuran go to the Warehouse where Harumichi is trying to save Yasu.
-Friends with Rindaman.
-Cares alot about his friends and his former school.
-Known to take cigarettes from others when he already has his own.
-Is well liked by senior and junior students.
-He is the cousin of Ishikawa Masao.