Kageyama was initially known by his former teammates at Kitagawa Daiichi as "King of the Court," which is a derogatory nickname that implies an autocratic nature. Despite being widely regarded as a prodigy and genius among many prefecture players and coaches, he struggled with controlling his frustration and expressing himself appropriately due to his sensitivity and childishness. However, after joining Karasuno, Kageyama was able to change his attitude for the better with the help of his new teammates and rediscover what it means to be part of a team. He grew more respectful of his upperclassmen, such as Sugawara and Asahi, and became more accepting of people whose abilities or views differed from his own. This helped him regain his confidence as a setter and understand the importance of teamwork and mutual trust in volleyball.
Currently, he is a member of Ali Roma, an Italian professional team in Italy Serie A.
In November 2018, he was playing as a setter for the Japanese V-League Division 1 team Schweiden Adlers.
He became a part of Japans national volleyball team at the age of 19, participating in the Rio Olympics in 2016.