In contrast to his appearance, Asahi is rather quiet and gentle and has difficulties accepting that he is Karasuno's ace, as he initially doesn't see himself as the ace. Asahi is said to have a "Glass Heart", taking everything that is said about him to heart, and becoming depressed because of it at times. He shows to be weak-willed at the beginning when he leaves the team before the first-years joined the team as he felt that he let down his entire team when they lost against Date Tech even though the team thought otherwise.

After coming back to Karasuno, he realizes that his will and desire to play volleyball is much stronger than he thought, and with the help of his teammates, he acknowledges his position as Karasuno's ace, even though he is still mocked sometimes by Daichi for not having any "ace-like presence", and gains self-confidence. While he still feels insecure about a lot of things and seems to be quite a scaredy-cat, he clearly states that he has no intention of letting anyone take his ace position away from him in later chapters, showing his development from the beginning.