|Height||184 cm (6'0½")|
|Weight||70 kg (154 lb.)|
|Hair Color||Dark Blue|
|Manga Debut||051. "Super Problem Child"|
|Anime Debut||021. "Enormous Trouble Makers! Hanamichi vs Miyagi"|
|Japanese Voice||Ryōtarō Okiayu|
|English Voice||Steven Bednarski |
Michael Pizzucato (Animax Dub)
Vincent Gutierrez (GMA Dub)
|[v · t · e]|
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.
Mitsui initially has shoulder length black hair with dark blue highlights when he became a delinquent along with his group and has a broken frontal teeth in both sides. He also has indigo eyes. When he returns to play basketball, he cuts his hair shorter and it was styled slick back and gains a false teeth to match up his broken frontal teeth. His hair later grows out and turns into a wavy style during their battle against Ryonan.
Like Takenori and Kogure, Mitsui wears a navy blue standard Shohoku winter uniform. As a initial delinquent, his jacket is open to show his white short sleeve loose undershirt. His summer uniform is the same as his winter uniform but its short sleeve button shirt is loose.
When he returns to play basketball training, Mitsui wears a white short sleeve shirt with the sleeves are folded to make it sleeveless, light purple trousers and white Asics basketball shoes with red linings. His actual training outfit is a maroon short sleeved loose shirt and black basketball shorts, he gains a red kneepad with black outlines where it supports his former left knee injury.
His Basketball Jersey is red and black and its alternate pallete is red and white.
When he was in middle school and as a Freshman in Shohoku, Mitsui's hair is in a short wavy style.
Regretful for quitting basketball for 2 years, he has returned with a renewed determination of conquering the nation he once dreamed of. While being competitive against Akagi during their 1st year, he has learned to accept the latter as the suitable captain for the team. He is also not afraid to stand up for a friend, just like what he did for Tetsuo; he insisted Ryu and his gang to beat him up instead of the latter.
While his lack of stamina is his main weakness, his great determination and trust for his team is what keeps him going, shown when he is totally worn out against Sannoh.
He went to Takeishi Junior High, where he was the MVP in his final year. It was at the final match where he met Coach Mitsuyoshi Anzai, who encouraged him not to give up hope until the last second, and enabled him to win the game. As a result, he went to Shohoku High School, having turned down Coach Taoka Moichi (who was also present at that game) when he offered him a place at the more prestigious Ryonan High.
He injured his knee during practice in his freshman year, and exacerbated his injury by returning to play before he had been healed. As a result he was not able to compete in the district tournament, and was disheartened into quitting basketball and becoming the leader of a gang.
He retained a great resentment toward the basketball club for a long time, and he and his gang picked on Ryota Miyagi during the latter's 1st year. A fight ensued, in which Miyagi beat Mitsui senseless, before taking a beating himself, knocking out a few of Mitsui's frontal teeth.
Both of them were in the hospital until after the practice game against Ryonan in Mitsui's third year. At this point, Mitsui attempted to ruin the basketball team by forcing them to fight against his gang and trying to get them banned from the regional tournament for fighting. In the end, Sakuragi's own gang - Yohei, Takamiya, Ohkusu and Noma - along with Norio Hotta and Mitsui's own friends voluntarily took the blame for the fight, and Mitsui was filled with remorse when he saw Anzai again. He rejoined the team and vowed never to fight again - a promise that he upheld even when he found himself cornered by some members of his old gang outside Shohoku.
Mitsui is best known on the team as a 3-point specialist, though his skills extend to other areas. During a practice match, he managed to shut down Sakuragi, playing Center. His defensive ability completely shut down Fukuda's scoring abilities. His 3-pointers helped Shohoku catch up when they were 12 points down against Shoyo and again when the team was 20 points down against Sannoh in the Nationals 2nd Round. He can also create a shot for himself, whenever facing his defender.
His major weakness is his lack of stamina due to his long break from playing basketball thus, in the later halves of games, he has not always been reliable as he was before. Like he was completely worn out in the game against Shoyo and Kogure has to sub in for him; Collapsed on court during the game against Ryonan; Totally worn out against Sannoh and can barely move. He has also lost his consistency in shooting 3-pointers and even misses despite being open.
The two players had history with one another before Mitsui stopped playing basketball. He once competed vs Akagi in order to determine who would be captain. He also considered Akagi's dunks somehow to be a challenge for him.
The two have known each other, when Miyagi beated Mitsui, knocking his frontal teeth, before been beaten by Mitsui's gang; which left them hospitalised for some time. Mitsui , with Tetsuo and his gang came to the gym in order to take revenge on Miyagi and force the team to fight his gang, so they could be disqualified from the tournament. During the showdown, Kogure reveals that Mitsui is a basketball player, once Mvp who got injured in the leg 2 years before the start of the series. While denying his interest about basketball, considerating it boring, Miyagi tells Mitsui he the one who couldn't forget about his past. With Anzai's sudden arrival, Mitsui, remorseful confesses that he wants to play basketball. Since then, Mitsui started to get along with Miyagi, ackowledging him as a friend and teammate.
At the end of the manga, with Miyagi as the new captain, Mitsui started to get into fights and quarrels with him because of his new strict personality, though, not at the same extent it used to be in the past.
Kogure and Mitsui used to friends during their first year of high school, until Mitsui receives a leg injury that made him unable to play basketball for some time. After Mitsui returns to the gym with the intention of destroying the basketball team, Kogure reveals to everyone about Mitsui's past, including his goal of the national championship. When Mitsui started denying his interest about basketball, to the point of knocking Kogure down. Kogure scolded Mitsui for giving up on his dream so easily, saying that he really has no guts and shouldn't give people so much expectations. Thanks to Anzai's call, Mitsui was finally able to redeem himself, admitting that he wants to play basketball. After the incident, the relationship between the two started to return to its formal shape.
Mitsui is very respectful to Anzai, and admires him very much, because he was the one who gave the confidence to Mitsui, during the match in middle school, telling him not to give up until the end, which enabled Mitsui and his team to win the match. Mitsui then decided to join Shohoku, because of him and his inspiring words. When Anzai entered the gym, Mitsui who came with the intent of destroying it, felt very remorseful, seeing his coach once again. Mitsui tearfully confesses that he really wants to play baskteball. Since then, Mitsui promised Anzai to never fight again, a promise that he even held up even while cornered by his former gang. During the match against Ryonan, when Anzai was hospitalised, Mitsui brought a photo portrait of him, and even began to pray for him as a sign of respect, which annoyed Sakuragi and Akagi, because thay believed that Mitsui treats him as if he was dead.
Hasegawa lost against Mitsui during Middle School and subsequently lost his confidence. But the time he saw him being a delinquent, he is in shock after seeing Mitsui's drastically changed behavior. Seeing each other again in the match against Shohoku and Shoyo three years later, he marks him with a box-and-one strategy. Mitsui overhears Hasegawa tell a Shoyo player that he won't allow him more than five points. This reinvigorated Mitsui's MVP talents and he consecutively shot several three points on the 2nd half. He managed to land 20 points during the game and cover the 12 point lead of Shoyo before tiring out to continue.
-To Anzai: "Anzai-sensei... I want to play Basketball."
-To himself (about Rukawa): "This guy always thinks he is the best. He is annoying, doesn't like to talk and has no respect for the others. But i have to admit it, he is really strong."
-To Minoru Matsumoto; "Kawata is Kawata, Akagi is Akagi. Then, who am i ? Tell me... I'm Mitsui. A person who will never give up."
- In the original English Dub of the anime, Sakuragi calls him "Missy" instead of "Mitchi".
- He is considered as one of the problem players because of the fight history. The others are Miyagi, Rukawa and Sakuragi.
- He is likely based on former NBA player, Craig Hodges. They both wore the no. 14 jersey and were three-point shooters.
- His left knee injury seen in both the manga and anime is revealed to be an Anterior Cruciate Ligament (ACL) and is a very common injury for basketball and volleyball players in real life. Additionally after his return to play basketball, Mitsui was seen checking his former left knee injury at the hospital.