GTO

Former juvenile delinquent Onizuka finds himself thrust into to role of high school teacher, facing students who behave just as he used to and an administration that doesn't trust him. Using the brash an unorthodox methods he picked up in his youth, Onizuka manages to reach through to his kids and help them with their problems.
(Source: Tokyopop)
Notes:
- Won the 22nd Kodansha Manga Award for Best Shounen Manga.
- The chapter count includes the 7 chapters extra GTO: Great Toroko Oppai♡ (Tomoko's Big Adventures) published in volumes 11 and 12, and one extra published in volume 25.