AppearanceMiya has golden yellow hair. Unlike his twin brother, Osamu, his hair is flipped to the right side and dyed blonde. His undercut and eyebrows are black, an indication of his original hair color. His eyes are large, hooded, and slightly drooping. He can usually be seen wearing a smile or smirk on his face.
Outwardly, Atsumu appears to be a carefree, confident person who's usually seen with a lazy smile on his face, though he enjoys provoking people and giving offhand compliments. He can be quite condescending, and somewhat selfish at times. Osamu has described him as someone who doesn't listen to others, doesn't return what he borrows, and lies habitually.
He also appears to be a perfectionist who has ridiculously high standards for himself and his spikers. He strives to provide the best toss for his spikers, but in turn, expects the spikers to perform at a high standard. If the spikers fail to meet his standards, Atsumu is not afraid to confront them directly and even call them trash, including his own twin brother. He is extremely sensitive when it comes to serving and how much noise is around him; if he's disturbed while serving, his outward personality changes completely and he becomes intimidatingly angry towards the disturbance.
Atsumu is a competitive person who hates losing; sometimes, these traits can veer off in a bad direction. Osamu has also noted that his twin brother's mental age drops by five years whenever he's in the middle of a game.
Atsumu lives in Hyogo Prefecture, and thus speaks in a Kansai dialect. He is currently a second year at Inarizaki High School with his twin brother, Osamu. He is recognized as the number one high school setter, as well as receiving the Best Server award during middle school and the Interhigh. Due to his top-notched skills, Atsumu is one of the few players invited to the All-Japan Youth training camp.
The twins have been playing volleyball since their elementary school days. In the fourth grade, they attended a volleyball workshop where they met their current teammate Ojiro Aran. During the workshop, Atsumu witnessed personally how a skilled setter brought out the potential of their spikers by sending them the best tosses. This piqued his interest in becoming a setter. At first, Osamu was picked as the setter due to being more skillful. However, according to Aran, Atsumu is said to have an irrepressible hunger as he pushes himself to improve. Eventually, Atsumu overtook Osamu as the official setter of the team.
Atsumu often got into conflicts with his teammates during junior high, especially when they failed to perform to his expectations. As a result, he was detested among his teammates. When asked about it, Atsumu revealed that he couldn't care less about being hated.
Tokyo Nationals Arc
Preparation for Nationals
Atsumu is one of the players invited to the All-Japan Youth Intensive Training Camp. During the first practice match, Atsumu chuckles lightly at the sight of Kageyama messing up. Sometime later, during a break, he approaches Kageyama as the latter was talking to Hoshiumi. After Kageyama tells Hoshiumi that he's not really affected by his jumping power, Atsumu laughs and calls Kageyama a cool and collected person. He then bluntly tells the first year that he initially thought Kageyama was a badass, but he can now see that Kageyama's just a goody-two-shoes. This annoys the latter, who glares at Atsumu hostilely.In the final practice match, Atsumu tosses to Kageyama for the first time. Kageyama spikes it with ease and tells Atsumu later that his tosses are easy to hit. In response, Atsumu simply replies that people who can't hit his tosses are scrubs. He then asks Kageyama if he enjoys spiking more than setting because Kageyama seems to be annoyed when he sets. Kageyama doesn't understand and stresses that he's a setter, and Atsumu leaves it at that. Kageyama questions Atsumu about what he meant by being a goody-two-shoes, and Atsumu replies that he just means Kageyama is obedient and honest.
As the players head home after the training camp, Atsumu says goodbye to Kageyama while telling him that they'll meet again at nationals.
Atsumu watches Karasuno's first match against Tsubakihara and notes that Kageyama is completely different from when he was at the camp. He then turns to Hinata, having seen his jumping power and speed, and wonders who he is.
Karasuno vs Inarizaki
Atsumu and his team, Inarizaki, faces off against Karasuno on Day 2 of the Spring Interhigh. In addition to his team being the second seed, Atsumu has a twin - Osamu - who plays opposite. While the two teams warm up in the sub-arena, Atsumu approaches Kageyama to tell him to give it his all since he hates playing against players who suck, indirectly referring to Hinata. When Kageyama assures him that Hinata is no pushover and will be a handful, Atsumu breaks into an intimidating smile but stops any further taunts.Once the match begins, Atsumu is the first to serve. He silences Inarizaki's orchestra as he requires absolute silence to concentrate. However, two girls not familiar with Atsumu's habit, cheer loudly. Atsumu hits a powerful spike serve that paints the line between Tanaka and Nishinoya. He then harshly glares at the two girls who cheered him on during his first serve, displeased with them for interrupting him. He makes his second serve but hits it out of bound. Later, Atsumu is seen questioning Hinata's max jumping power and his similarity to Kageyama as the type of guy who does as he pleases after Hinata tries experimenting with something during their match.
As the game progresses, Atsumu shows off his aggressive playmaking by setting off the first touch to Ojiro, who scores before Karasuno could react. His cool demeanor is finally broken when Karasuno counters with a minus-tempo broad attack as Atsumu can't help but fanboy over the freak quick after witnessing it up close. On his next serve turn, Atsumu hits a floater aimed right at Nishinoya, who fails to save the ball. He observes that Karasuno is not particularly shaken by his serves and instructs Osamu to not mess up the timing of their next attack. Atsumu hits another floater, and this time, Karasuno receives it. Once the ball returns to Inarizaki's side, Atsumu successfully executes a minus-tempo quick with Osamu, taking everybody by surprise. Afterward, Atsumu admits that his accuracy is not as precise as Kageyama's, but he has the urge to imitate flashy moves. The match continues with both teams using their quicks against each other. Atsumu deduces from watching Karasuno's previous matches that Kageyama has a habit of forcing a quick after a botched receive. It appears that Atsumu has informed his team about this beforehand as all three blockers jump at Hinata to shut down his spike.
Nationals (Post Karasuno vs Inarizaki)
|High School Statistics|
- Spike Serve and Jump Floater: Atsumu is known as the "Dual Wielder" for his mastery of both the spike serve and jump floater. His spike serve is packed with power while his floaters are fast and unpredictable. This makes it incredibly hard for his opponents since they won't know which type to prepare for until the last minute. However, Atsumu has some peculiar habits regarding his serves. He takes 4 steps from the end line for a jump floater and 6 steps for a spike serve. He also requires absolute silence during his serve or else risks losing his concentration.
- Hybrid Serve: After observing Russian volleyball player Mikhail Orlov, Atsumu successfully adds a third type of serve to his repertoire and evolves into a "Tri Wielder". His hybrid serve uses the same toss and number of steps as a jump floater but is packed with the intense spin of a spike serve. With three serves in his arsenal, Atsumu is able to trick opposing defenders into positioning themselves incorrectly and thus making receiving any of his serves incredibly difficult.
- High-Quality Tosses: Kageyama has described Atsumu's toss to be incredibly easy to hit, thus creating the impression that the spikers have improved. Atsumu is extremely dedicated to providing the best toss for his spikers and would try to use an overhand toss even in difficult positions. An example is when Atsumu gets into a crouched position while tossing overhand with the same speed and fluidity. Due to this, Kenma has described him as the "prototypical setter." His talent as a setter is so immense that he can mimic Kageyama's toss for the minus-tempo quick on the spot.
- Minus-Tempo Quick Set: Like Kageyama, Atsumu is capable of making use of the Freak Quick with either his twin Osamu or Hinata. While he misses the toss more often than Kageyama does, he has enough precision and speed in his tosses to make full use of the quick.
- Sharp Game Sense: In addition to his ability to make the best use of his spikers, Atsumu is an expert on pressuring his opponents. He doesn't hesitate to copy Kageyama and Hinata's signature quick to shake Karasuno up. He is also very observant and figures out Kageyama's tendency to toss to Hinata after a botched receive.
- Dump Shot Feint: Atsumu can bait his opponents into a foul by pretending to do a dump shot before switching to set up for a toss. This relies on the rule forbidding the blockers to reach over the net for the ball unless it's an offensive play. Atsumu is seen using this trick to gain an advantage in battles at the edge of the net.
The twins have been interested in volleyball together since elementary school. The two are each other's biggest rivals and pushes each other to improve due to their dislike for losing. On the court, they have perfect chemistry and can perform a God-Like Quick without prior practice.
Atsumu first took notice of Hinata when he went to observe Karasuno's match against Tsubakihara. Atsumu didn't think highly of Hinata at first and indirectly referred to Hinata as "people who are real crap at the game." However, Atsumu's opinion changed during their match after realizing Hinata's potential as a player and his "trust" as a spiker to his setter. At the end of the match, Atsumu called out to Hinata declaring that someday he will toss to Hinata. Later, the two would become teammates in MSBY Black Jackals, thus fulfilling his earlier promise.
- "People who can't hit my tosses are nothin' but scrubs." (To Kageyama , Volume 25 Chapter 219)
- "Well, with a dig all you've got is two arms. But going overhand means you've got ten fingers to use. Ten is more than two. More support is better, so I went overhand. Cuz I'm a setter." (To Suna , Volume 32 Chapter 279)
- "One day, I'm gonna set for you. But before that happens, I'm gonna whup the pants off ya in next year's Inter-High, so you'd better be ready." (To Hinata after their Tokyo Nationals second-round match, Volume 33 Chapter 291)
- "For that prickly first impression, you gave... Out on the court, you're an awful sweet goody-two-shoes, ain'tcha." (To Kageyama , Volume 24 Chapter 215)
- "Don't interrupt my serve again... You oinkin' pigs!" (Volume 28 Chapter 249)
- "I'll toss to ya one of these days... But before that happens, I'll destroy you at the Interhigh, so you better brace yourself." (To Hinata after their Tokyo Nationals second-round match, Volume 33 Chapter 291)
- "Us foxes...The kitty-cats...and then those seagulls. It took aaall three of us to bring that monster down."(Thoughts on Hinata, Volume 41 Chapter 365)
- "Back in the day, I remember our old club captain said he didn't like the team motto. I've always liked it, but now I feel like I'm finally gettin' it. In volleyball, the past is gone. There ain't no such thing as memories. All you need is right here. All I need... are my muscles!" (To himself, Chapter 391)
- Favorite Food: Fatty Tuna .
- Current Concern: It's the season where your fingertips get really dry.
- It is revealed that Atsumu is the older twin. 
- When Atsumu Miya and Osamu Miya were fourth-graders, they found Ojiro Aran cool for his foreign-sounding name.
- Atsumu wears black gym shoes with blue accents.
- The Miya brothers attended the same Inarizaki Group Training Camp as Ojiro Aran
- Although Coach Ukai listed Osamu's, and by extension Atsumu's, age as 16, the Miya twins should have already been 17 by the Spring Interhigh due to their birthday in October.
- He is currently second in serve rankings under Tobio Kageyama.
- He refers to Ojiro Aran as someone he should look up to because of his ability to shut down jokes and always have a comeback ready.
- Yako (野狐; lit. field fox) is a spirit possession of foxes in Japanese folklore. Unlike how most of the other schools were named, Yako Junior High School uses the actual kanji of what it's referencing.
- Atsumu (侑) - Urge to eat
- (Metaphorically cannot satisfy his hunger for winning)
- Miya (宮) - Shrine