Mitobe has medium-length black hair that is parted to the sides, but with one strand of hair between his eyes. He also has very thick eyebrows. One of his distinctive features is that he always has his mouth closed, even when playing, and never speaks.
He wears the Seirin High jersey with the number 8. He is also one of the tallest members of the club.
Mitobe is just as determined to win as the other players at Seirin High, but unlike the others, he doesn't show his feelings that often. Most people know him as a quiet, hard worker. According to Riko Aida, no one has ever heard Mitobe talk.
Mitobe has a large family and is in charge of making breakfast every morning, thus he is skilled in household chores and cooking. He is naturally caring and often worries about the well-being of his teammates, especially the underclassmen and Shinji Koganei, whom he has known the longest. Somehow, despite the fact that he is mute, most people understand what he is thinking and can even hold a conversation with him, especially Koganei, who seems to understand Mitobe perfectly. He also seems to be somewhat of a pushover, since both Koga and Junpei Hyūga can boss him around easily.
Mitobe joined the Seirin High team together with Shinji Koganei. Koga reveals that Mitobe had been playing since Junior High school while he himself was a beginner. Koga claims that he started playing basketball because he watched Mitobe and thought it looked fun. Later, Koga also revealed that Mitobe was a power forward in Junior High School.
When the team shouted their resolve on the roof to convince Riko Aida, Koga yelled Mitobe's name and class for him and Mitobe was shown looking relieved afterwards.
Mitobe is first seen, together with the other regular members, distributing flyers and recruiting for the basketball team. (Shinji Koganei encourages him to shout, to no avail).
Seirin vs Kaijō
Mitobe is one of the tallest of the team, so he block shots and plays low and high post. In the match against Seihō High, he also showed that he can dunk. He has been playing basketball since Junior High school.
Mitobe is a veteran when it comes to defense, especially guarding players bigger than him, through his pressure defense. He does this, not by blocking their shot, but by not letting them do what they want to do; in the process the opponent was forced to miss. He taught this method to Taiga Kagami, who used it against Dad  and Kenichi Okamura in their matches. He is also mentioned to be more than good enough to handle Chihiro Mayuzumi and can find pass targets based on the balls position even if misdirection is used. He is also good at blocking shots.
Just as the other second years of Seirin High, Mitobe has spent the last year training on one particular technique: His hook shot. Using his body to position between his defender and the ball, he shoot with his free hand (its trajectory looking like a "hook"), that is almost impossible to block.
Theoretically, you can jump off both feet (jump hook), one foot (hook shot/sky hook/baby hook), or sweeping the shot while having the body gliding across the court (sweeping hook/sky hook/running baby hook).
- The name Rinnosuke means "dignified, severe, cold" (凛) (rin), "this" (之) (no) and "help, rescue, assist/assistant/assistance" (助) (suke).
- Rinnosuke's surname Mitobe means "water" (水) (mi), "door" (戸) (to) and "part, department, category" (部) (be).
- On the first character poll, Mitobe ranked 11th, with 519 votes. He ranked 19th on the second poll, this time with 227 votes. He ranked 3rd on the Center Division of Kuro Fes' character poll with 2746 votes.
- On last year's test results, Mitobe ranked 74th out of 300. His best course is Science.
- According to CHARACTERS BIBLE:
- His hobby is Photography.
- His specialty is cooking and Cat's cradle.
- His favourite food is Tuna Donburi.
- His motto is: "Honestly, humility and quietly."
- According to KUROFES:
- His best subject is Chemistry.
- He is in the Health Committee.
- His family is made up of his mother, father, 6 younger brothers and 3 younger sisters.
- He dislikes talking.
- His best basketball play is hook shot.
- The type of girl he likes is a quiet person.
- He spends his days off playing with his family.
- He started playing basketball because of club recruitment.
- The player that he has his eyes on is Kobori.
- Mitobe won the sauna battle for Seirin against Tōō Academy.
- Mitobe has 6 younger brothers and 3 younger sisters, all who support his basketball team greatly and all share his trademark large eyebrows. For the Winter Cup finals, his siblings made a "Go! Seirin!" banner to support them.
- One of Mitobe's brothers attends Shūtoku High.
- Shinji Koganei mentions Mitobe in both of his Character Songs.
- Koganei and Mitobe both have part-time jobs.
- Mitobe's move is a reference based off of Kareem Abdul Jabbar's Skyhook, the most notoriously unblockable shot in NBA history.
- Kuroko no Basuke chapter 95, page 19
- Kuroko no Basuke chapter 96, page 8
- Kuroko no Basuke chapter 114, page 16
- Kuroko no Basuke chapter 22, page 22
- Kuroko no Basuke chapter 14, page 13
- Kuroko no Basuke chapter 149, page 18
- Kuroko no Basuke chapter 23, page 5
- Kuroko no Basuke chapter 37, page 11
- Kuroko no Basuke chapter 128, page 19
- Kuroko no Basuke chapter 229, page 9
- Kuroko no Basuke Special CD Vol. 23
|2nd years||Junpei Hyūga • Shun Izuki • Rinnosuke Mitobe • Shinji Koganei • Satoshi Tsuchida|
|1st years||Tetsuya Kuroko • Taiga Kagami • Kōki Furihata • Hiroshi Fukuda • Kōichi Kawahara|
|Other||Tetsuya #2 • Kagetora Aida • Alexandra Garcia • Kenji Takeda|
|Former players||Teppei Kiyoshi|