Being the only one in his middle school team Kitagawa Daiichi to take the match against Hinata's middle school seriously, he is first and foremost irritated by Hinata's stunning jumping abilities that he calls wasted on a meager team as he was in. After defeating Hinata, him and Kageyama swear to each other to become better than the other and defeat the other.
Seeing as they both then join Karasuno, they are forced to join forces instead of going against each other which both boys heavily dislike at first. Kageyama refuses to play with Hinata although he is very well aware of the hidden abilities Hinata has but needs to play with him anyway as their captain Daichi practically threatened him to decide whether he wants to get along with Hinata and play with him or play for Karasuno but not as a setter. He doesn't want to toss to Hinata at first, tossing exclusively to Tanaka, but acknowledges his will as Hinata attempts to spike any of the tosses he makes, no matter how difficult they were.
Their relationship becomes much better then, as Hinata does something none of his former teammates for him: Hinata spikes a toss that used to be called impossible to spike and calls out to him that he will spike any toss Kageyama will give him, no matter how. Realizing Hinata managed to spike it with his eyes closed and putting 100% of trust into Kageyama's toss, he promises right back to make Hinata the strongest on court as long as he is the one who tosses.
They are seen to hang out a lot after training too, namely while at school, even though they are not in the same class, implying that they get along fairly well (despite both of them refusing to admit that). Called a "chemical reaction" by Takeda which allows them to be perfectly synchronized on court, they keep playing together being called "Karasuno's Secret Weapon" for their Oddball Quick Strike.
In chapter 79, however, Hinata proposes to change their Oddball Quick Strike: Instead of spiking it with his eyes closed and relying on trusting Kageyama to toss it perfectly, he wants to be able to spike any of Kageyama's tosses like that with his eyes opened. Kageyama remembers to have apologized to Hinata after their loss against Aobajousai for having tossed to him, trusting for Hinata to be able to make a point. Still, even after Hinata's explanation that he doesn't want Kageyama to take the blame for a mistake he made, Kageyama objects to that idea, as do Ukai and Sugawara .
He tries to make clear that the Oddball Quick Strike is fine as it is now and that Hinata should focus on training other basic things instead of wasting his time thinking about a quick strike that is definitely working because he is the one tossing, feeling obviously dejected as to why Hinata refuses to rely on him anymore. He proposes to show Hinata what he meant and they try to make the Oddball Quick Strike with Hinata having his eyes open but fail to achieve anything. They start fighting over this matter, attacking each other to be ultimately scolded by Tanaka for their behavior.
He later goes and accidentally meets Oikawa who explains to him that instead of making Hinata forget about his idea, Kageyama should encourage him and give it a try as it could be incredible if Hinata could pull that off. Kageyama declines saying that Hinata doesn't have the skills to do so but Oikawa makes clear that he should consider Hinata's will to spike and to receive his tosses. Oikawa leaves, remarking that it would be cowardly to rely on things that always work and reminding Kageyama of his old behavior.
After that, Ukai calls Kageyama, meets up with him and tells him hastily to change his way of tossing as they are technically the best tosses but not the best for Hinata to spike. They speak about a halted toss that leaves the force with which it is spiked to the one who actually spikes, making it a more flexible toss than the one Kageyama used before. Realizing that Hinata would put a 100% into that toss as it is the type of toss he wants, Kageyama decides to start training it until they all go to the summer training camp.
There he tries out the new toss but fails to do so properly. Still, Hinata is able to save the failed toss by spiking it with his left hand which makes Kageyama realize that Hinata will definitely always be able to receive the tosses. In one of the training matches, Kageyama happens to unconsciously toss a ball to Hinata as he used to as he noticed how stressed out Hinata was and they almost start fighting again but the situation clears up just fine as Kageyama explains he didn't do it on purpose but also states that even though he thought they'd already be able to play together again, he doesn't want to do so yet. They start training separately yet, getting along almost as good as before their fight though and continuously making sure the other doesn't slack off.
In their training match against Fukurodani Academy in chapter 93, they manage to bring back the Oddball Quick Strike, and this time with Hinata's eyes opened. They celebrate it and Hinata states, for the first time straight to Kageyama's face, that he was really amazing.
Ойкава был семпаем Кагеямы в средней школе. Тоору относился к нему с презрением, в связи с тем, что Кагеяма был гением с младых лет. После просьбы Кагеямы научить его подавать, Oйкава чуть не ударил его - Иваизуми помешал. В итоге Тобио научился подаче лишь благодаря постоянному наблюдению за Тоору. Брюнет верил, что превзойдя Ойкаву, он станет лучшим связующим в префектуре. Их соперничество продолжалось и в старшей школе: хоть Кагеяма и достиг своего апогея в Карасуно, школа все равно проиграла Аобаджосай в предварительном матче старших школ. Они оба насмехались друг над другом во время матча, а Ойкава наслаждался давкой над потерявшим хладнокровие Кагеямой. Тот, в свою очередь, неохотно уважал бывшего семпая и его способности, как волейболиста, но все-таки пошел к нему за советом после решения Хинаты. Первоначально Ойкава отказывался разговаривать с Кагеямой, но после смягчился и сказал дать Шое шанс. По его мнению, если Тобио откажется пробовать новые вещи, то безжалостное прозвище "Король Площадки" снова станет ему характерно.
Сугавара признаёт способности Кагеямы, называя его "связующим-первогодкой", но при этом не желает сдавать ему позицию связующего. Несмотря на это, он даёт понять тренеру Укаи, что не расстроится, если не будет играть так уж часто, и обращается с Кагеямой как с младшим учеником, которого он может натаскать (особенно это касается общения с командой), и у которого может научиться чему-то сам. Сугавара показывается как "укротитель" Кагеямы, особенно в ранних главах, когда умерить пыл Тобио было его задачей. Кагеяма признаёт способности семпая и всегда открыт для совместной работы и обучения от него.