|Other names||'Samu (Atsumu Miya)|
|Date of birth||October 5|
|Height||183.8 cm (6' 0.4")|
|Family||Atsumu Miya (twin brother)|
|Team|| Yako Junior High (former) |
Inarizaki High School
|Occupation||High School Student (2nd Year, Class 1)|
|Affiliation||Inarizaki High School|
|Image gallery (23)|
He has a large build and is very similar in appearance to his brother, which shows that they are most likely identical twins. Osamu's hair is dyed gray and his fringe is flipped to the left side.
Osamu appears to be the calmer of the Miya twins with a laid back and deadpan personality. Despite his outward demeanor, Osamu is highly competitive and becomes heated even if it isn't obvious on the surface. However, with enough provocation he gets angry and physical. In that state, he unleashes his filter and begins spewing profanity. So far his brother is the only person to get him this emotional.
He's shown to have a sense of humor, especially regarding Atsumu, whom Osamu teases whenever he messes up.
Osamu lives in Hyogo Prefecture and attends Inarizaki High School with his twin brother. He is currently a second year and is a member of his school's boys' volleyball team.
Together with his brother, Osamu has been playing volleyball since his elementary school days. In the fourth grade, the twins attended a volleyball workshop where they met their current teammate Ojiro Aran. They thought foreign sound names are cool and came up with the nickname 'Samu and 'Tsumu for each other.
When asked if he wanted to be a setter, Osamu turned it down saying he prefers to spike. Despite that, he was choosen to be the setter for his junior high team until Atsumu overtook him. According to Aran, Osamu was the more skilled twin with Atsumu constantly challenging him. 
Tokyo Nationals ArcEdit
Osamu made his first appearance with the Inarizaki team on the second day of the Spring High Tournament as they face off against Karasuno. During his serve turn, Osamu waits out the full eight seconds before serving. His serve ends up perfectly received by Nishinoya and ends in a point for Karasuno. Later, although reluctant, Osamu performs the God-Like quick with his brother Atsumu delivering the ball to his exact spike point. When Aran comments about the trust between the brothers, Osamu denies it is trust but it isn't needed since he just knows the ball will come to him. The twins continues to score with their new quick until Tsukishima shuts it down. After Tsukishima rotates to the back, Osamu finds himself in a 1-on-1 with Hinata commit blocking him. Although Hinata manages to block Osamu once, Osamu quickly gains the upper hand and spikes pass Hinata's block with ease. The two players end up in a jousting battle at the edge of the net with Osamu dominating. Later, Osamu is seen half-assing a run-up attempt since he is only acting as a decoy. He got an earful from Atsumu, who accuses him of being afraid of Hinata's blocks. Osamu says no but is taken aback when Hinata suddenly questions him if he is being serious. In his next quick attack attempt, Osamu is forced to hit a straight when Hinata choked off the path for a cross. His spike is received and eventually results in Karasuno's break when they employed their blend-and-distract tactic. After this play, Osamu mentions that he is suddenly feeling hungry to Atsumu's confusion.
After Karasuno took the first set, Inarizaki turned up the heat and overwhelmingly dominated their opponents. When Atsumu got the first touch of a chance ball, Osamu acts as a backup setter to set a quick to Suna, demonstrating just how the Miya brothers complement each other on the court. However, he and his teammates begin to show signs of unstability once Karasuno starts exerting pressure. When Atsumu taunts Osamu about beating him in service aces, Osamu becomes agited enough to lose control in his serve and hit it hugely out of bound. Inarizaki eventually regain their composure and won the second set once their captain Kita is subbed in.In the third set, Osamu continues to show off his all-rounder prowess. He successfully receives a jump floater serve from pinch server Kinoshita, ending Karasuno's serve in one turn. He and Atsumu eventually forced Karasuno into a corner when Osamu pulls off a minus-tempo toss to Atsumu. With Inarizaki gaining all the momentum, the twins continue to make bold and aggressive plays. Almost as a response to his quick being limited and blocked by Tsukishima, Osamu re-sets a toss to Aran after Atsumu sends him a toss on the first touch. The play successfully fools Karasuno's blockers as Aran blasts a spike to open space. The spike ends up received by Hinata and results in a long hard-fought rally that concluded in a lucky net-in for Inarizaki. Despite widening their lead, Osamu recognizes the change in atmosphere with Karasuno. He has been quietly observing Hinata for a while and finally voices his thoughts to Atsumu. Osamu compares Hinata's passion for the sport to eating a meal as well acknowledging just how infectious such hunger can be to his teammates. True to his observation, Karasuno regains their composure and soon caught up to Inarizaki.
With the match counting down to its final points, Osamu is shown to be just as fired up if not more so than Atsumu. Despite being less than enthusiastic about the God-like quick in the beginning, Osamu is now the one initiating the attack and exerting pressure on Atsumu to send the toss to him. Atsumu fully relishes in his brother's greed to score, and decides there's no one better to use as decoy much to Osamu's annoyance. When they saw Karasuno's receivers out of formation after returning a nearly impossible ball, the twins take advantage of the momentary confusion to attempt a minus-tempo back attack. The surprise attack takes Karasuno by surprise but is ultimately shut down when Hinata and Kageyama successfully block it, thus giving Karasuno the match point. Afterwards, Osamu realizes that they went too wild with their last play.
After their loss, the twins try to apologize for losing the final point before Kita rejects their attempt. Kita tells them that they last play is not a mistake, but rather it is because of their opponent. When Kita expresses how proud he is of his teammates and his regret for not being able to play with them longer, both Atsumu and Osamu claim they will be teammates Kita will be proud of.
It is said that "even if you take down Miya Atsumu, his twin Osamu will be right there to pick up the slack."  Despite being a wing spiker, Osamu proves he is just as capable as a setter. He has shown the ability to set for the Twins Quick Attack Minus Tempo - Inverse with his twin Atsumu and even resets a toss directed at him while transitioning from spiking form.
Osamu is almost always seen together with his twin Atsumu . As such, Osamu is familiar with Atsumu's every habit, including Atsumu's tendency to lie and never return borrowed things. Like brothers, they are quick to quarrel and fight, but they get over it just as quick. Osamu is frequently seen teasing his brother, especially when Atsumu messes up in a match. They are each others biggest rivals and constantly push each other without even realizing. Nevertheless, Osamu acknowledges that Atsumu's passion for volleyball burns brighter than his own, and is at peace with himself when only Atsumu got selected for the All-Japan Youth Intensive Training Camp. 
Their nicknames for each other, 'Samu and 'Tsumu, came about when they met Ojiro Aran in fourth grade because they wanted to sound foreign.
The two faced off when Hinata is assigned to commit block Osamu against the Twin Quick Attack. Although caught off guard at first, Osamu quickly gains the upper hand in both spiking and jousting at the net. After Hinata adapts and alters his tactics to successfully counter Inarizaki, Osamu mentions that he is feeling kind of hungry. He continues to observe Hinata throughout the match, and comes to the conclusion that Hinata's play style is akin to eating rice/meal. Osamu recognizes Hinata's hunger for the sport and is aware of how infectious such hunger is to other players.
Osamu is on good term with the rest of his teammates, enough that he and Atsumu will play jokes on them. Their usual target is Aran , who is often to play the straight man to the twins' gags. Osamu and the rest is shown to be terrified of Kita's cold logic. However, he has nothing but respect and admiration for Kita deep down.
- Favorite Food: Rice
- Current Concern: Not being in the mood to decide what to eat on the last day of his life.
- When Atsumu Miya and Osamu Miya were fourth graders, they found Ojiro Aran cool for his foreign-sounding name
- The Miya brothers went to the same junior high school as Ojiro Aran
- Osamu (治) - To rule / govern
- Miya (宮) - Shrine
- "The thing is Atsumu, when it comes to the love of the game...that flame burns a bit brighter in you than in me, you know?" (To Atsumu, Chapter 279)
- "When you're hungry, and you eat a small mouthful of something...it makes you even hungrier." (To Atsumu, Chapter 282)