Birthdate: 18th February 1976 in Inogashira
He is a teacher in Seirin Academy. His subject is math.
He's nicknamed from Onizuka "Tessy" or "Tadai-kun", because he keeps pronuncing wrong his name.
He's secretly obsessed with Azusa Fuyutsuki (he even spies on her and has a room full of photos of her). Although on the surface he usually behaves politely with almost anyone, on the inside he's rather viscious and manipulative.
He suffers from an inferiority-complex towards both his brother and father, both of them are succesful politicians.
He hates Onizuka and even tries to kill him. Teshigawara is the symbol of modern frustration caused by the constant competitiveness in Japanese society which the author of GTO criticizes so much.
Suguru Teshigawara was born into a family of politicians (father side of the family). His father was always impressed by Suguru's older brother, but looked down on Suguru's mediocre grades and weak body. This led his father to send Suguru to cram schools to increase his grades, and sent Suguru to swimming classes to improve his body. However Suguru was unable to achieve his father's expectations, which led to more stressful activities being added onto his lifestyle.
Suguru always went to an old woman in order to relieve some of his stress by talking about his problems. The old woman told Suguru that he shouldn't listen to what his father tells him, and have courage to not listen what his father tells him to do. Later Suguru got in trouble at school for stabbing a person in the leg who was bullying him. His father became extremely angry at him, so he went to talk to the old woman only to discover that she had passed away in her house.
After the old woman's cremation, Suguru had a delusional revelation that the old woman didn't die but had merely became a butterfly after shedding its caccoon. Suguru thought that he was only a larva which didn't become a butterfly, which led him to dedicate all his time and effort into studying to be a politician like his successful father and big brother. Suguru Teshigawara graduated from the good Tōdai (Tokyo Daigaku) University. Afterwards Suguru tried with extreme effort to pass the government test which would lead him to become a politician, but discovered that he had failed the test. (revealed later that government officials had forced Suguru to fail because of the scandal surrounding his family)
Suguru later went on to be a teacher at Seirin Academy, which he thought was the best alternative position that he could receive. Suguru would meet Onizuka and try to get him fired or killed, in order for Onizuka to stay away from his love-interest Azusa. Suguru would repeatedly fail to discredit Onizuka, and push his mind to the breaking point of insanity.
Later Suguru kidnapped Azusa, in order for the two to get married by force. However this failed by the combined efforts of Onizuka and Azusa's little sister. This failure into obtaining his love-interest Azusa pushed Suguru into a delusional insanity, and later reminisced about his past and his current situation. Suguru in his delusional state shot Onizuka, hurt many pedestrians on the streets, and later tried to takeover Seirin Academy. This resulted in the police to make a wanted poster of him on the news.
Suguru would then get beaten up by Onizuka for all the trouble he had caused, and was going to be arrested by Onizuka's cop friend. Before he could be apprehended, his big brother appeared telling Suguru didn't have to feel inferior to him and their father because they were both fired from their political positions. This recent news led Suguru into complete insanity and tried to blame Onizuka for all the problems that had occurred to him, which led Suguru to try and bomb Onizuka on the school roof but failed. Suguru in his despair realized that he didn't have the courage to take control of his life, and was too afraid of his father to disobey his orders. Suguru at that revelation tried to commit suicide, but was saved by Onizuka and made peace with him.
Suguru was later arrested by the police and dismissed from Seirin Academy. Suguru, Suguru's older brother, and two police officers shortly visited Suguru's father before being taken into custody for the damage that he had caused. However Suguru's father was completely delusional and believed that he and Suguru's older brother were still politicians, and didn't show any attention to Suguru at all.
Suguru was last seen carving a buddha statue in his prison room, and sensed that danger had fallen onto Onizuka (when Onizuka almost died from his head injuries).
Anime & Manga Differences
- In the anime he leaves for a while when he gets a nervous breakdown after Onizuka beats him in a test.
- In the manga he goes to jail for shooting a policeman but redeems himself with Onizuka's help.