Isogai is a kind, cheerful, and reliable person. He is modest, not at all boastful, and helpful. Isogai has been noted to have good leadership qualities and personal virtues, and due to that he's able to see all the individual strong points in his classmates. Because of these traits, he is considered to be an ikemen, which not only means handsome, but can also imply a flawless personality. However, despite having the personality of a gentleman Isogai has an extremely casual tone to his speech, often cursing and talking like a regular teenager.