Noboru Yoshikawa is a student at the Holy Forest Academy, and did not have a good time before Eikichi Onizuka arrived, being the victim of bullying, mostly from Anko Uehara and her group (Miyabi Aizawa replaces Anko's role in the live-action). He is extremely good with video games and is somewhat of an otaku, but proves to be quite handy with making things. He also has an eye for girls and pays a lot of attention to them, as seen when Aizawa's plan to charge Onizuka with embezzlement when the group tries to identify the girls Aizawa paid to follow her plan.
Anko's bullying is so bad it included bruises over most of his body as well as writing made with permanent marker around his private parts, it makes Noboru attempt to commit suicide twice, both times by leaping off the roof of the school, and both times resulting in him being saved by Onizuka, at the cost of Vice-Principal Hiroshi Uchiyamada's car (note that only the second attempt was caused by Anko's gang in the manga version; Noboru mentions some thugs in Class 2 as the cause of his first attempt). The two strike a quick friendship, which works for Onizuka, as Noboru has plenty of items that he wants to "borrow". His loyalty to Onizuka is by far the strongest, seen when he willingly sells his game collection to help cover Onizuka's debt.
While on the school trip to Okinawa, he gets room assigned with Anko and her friends by Onizuka. In retaliation for Onizuka and Noboru's antics, he gets tied up and led away into the dense jungle by the girls, but they all end up getting lost and rely on him for help. Despite the abuse, he saves Anko's life after she falls off a cliff, getting separated from the others. As the rest of the events of the manga unfolds, Noboru begins to enjoy Anko's company enough that she begins to feel affectionate to him.