Slam Dunk centers around Hanamichi Sakuragi, who starts as a delinquent outcast, becoming the leader of a gang. Hanamichi, being
very unpopular with girls, has been rejected by them fifty times. Yet, he finds out that Haruko Akagi is the girl of his dreams,
and is happy when she's not scared of him like all the other girls he has asked out.
Haruko Akagi, who recognizes Hanamichi's athleticism, introduces him to the Shohoku basketball team. Hanamichi was reluctant to join the team at first because he had no previous background in any sports and thought that basketball was a game for losers (also because the fiftieth girl rejected him for a basketball player). Sakuragi, despite his immaturity and hot temper, proves to be a natural athlete with potential and joins the team in order to impress Haruko and prove that he is worthy of her. Kaede Rukawa — Sakuragi's bitter rival (both on the basketball court and love, even when Rukawa doesn't acknowledge Haruko's crush on him), the star rookie and a "girl magnet" - joins the team at the same time. Hisashi Mitsui, an ex-junior high school MVP (Most Valuable Player), and Ryota Miyagi, a short but fast player, both also rejoin the team and together these four struggle to complete team captain Takenori Akagi's dream of making Shohoku the national champion. Together, these misfits gain publicity and the once little known Shohoku basketball team becomes an all-star contender in Japan.
Hanamichi Sakuragi is the main protagonist of the series. At the beginning of the series, Sakuragi is a slacker, good for nothing other than fighting delinquent, who's the leader of the feared "Sakuragi Legion", which consists of his four friends Mito, Noma, Ohkusu and Takamiya. Sakuragi's quest for love is nothing but humiliating. He is always trying to ask girls out, but is rejected constantly, the fiftieth rejection occurring at the start of the series. Haruko's encouragement led to him to join the Shohoku basketball team. However, as a complete beginner, he is not able to keep up with the rest of the team at first, despite his physical attributes (great height, athleticism, stamina, speed and leaping ability). With just 4 months, he has become a fully realized basketball player and is now considered a player that Shohoku cannot afford to lose.
Takenori Akagi is the captain of the Shohoku basketball team and Haruko's older brother. Despite not thinking too much of Sakuragi at first (who addresses him as "Gori" for gorilla due to his immense physical presence), he actually realizes Sakuragi's potential as a basketball player. Serious and disciplined, Akagi's dream is to lead Shohoku to the National Championship. His determination is shown in the match against Kainan, where he played on despite a serious injury to his ankle. Akagi considers Jun Uozumi of Ryonan to be his rival, though their rivalry is not antagonistic; indeed, there is respect that borders on friendship.
Hisashi Mitsui is the Shooting Guard of the Shohoku Basketball Team. Though he was on hiatus due to his
knee injury, he still has the skills to put the team on a win.
Despite having the opportunity to join more prestigious high schools like Ryonan, he choose to go to Shohoku because of Coach Mitsuyoshi Anzai. Anzai had given him the courage to win in the Junior High tournament by encouraging him during the last seconds of the match. However, an injury to his left knee in a training session in his first year at Shohoku interrupted his basketball career. An imprudent early return to the court reinjured the knee more severely, leading to a basketball hiatus of over a year.
Ryota Miyagi is Sakuragi's closest friend on the team. After an initial misunderstanding that caused conflict between them (he was fighting Mitsui when Sakuragi and Ayako came around, and he thought she was dating him), both found comradeship in the fact that they had both been unlucky in love, although Miyagi, having only been rejected 10 times, still falls short of Sakuragi's record who was rejected 50 times.
Kaede Rukawa is, in many ways, the opposite of Sakuragi - attractive to girls, skilled at basketball, very cold and unfeeling. The only traits they share are that they are good fighters and not academically inclined. But when it comes to basketball he shows a passion to be the top of his game. He is usually stoic, and the only time in the series he is shown smiling is when he realizes that Eiji Sawakita is a better player than him.