When Hanai was in middle school, he used to be the cleanup hitter and the captain of the baseball team. Currently, he is the captain of the Nishiura High School baseball team, and is considered to be the second most talented among the team (right under Tajima).
Hanai shaves his head, but it's not always apparent due to him wearing hats. He is the tallest among the members, standing at 181 cm, though due to being a first year, he is still thin for his height.
Hanai is a level-headed and relatively smart and observant person. He is reliable, knows his own abilities, and is willing to help when needed. He is noted by Mihashi's mother to be a very polite and well-mannered boy, although he appears to be rather rude to his own mother, which she also notes. It has been stated that he is type of person who would stress out if he left a person in trouble alone. He is also not afraid to talk things over to their coach when needed. All of his qualities got him unanimously voted to become team captain.
However, he has an overwhelmingly strong inferiority complex when it comes to Tajima, who he considers both his teammate and rival. He tries to surpass Tajima and compete with him, but he often comes up short and gradually loses his confidence. However, he later regains a little of it back when Tajima admits that he is jealous of Hanai's tall stature, which allows him to hit a homerun - something Tajima is unable to do.
Hanai has a great respect for baseball, despite claiming that he is no longer serious about it when the team first forms. He often knows what to do for the team before Momoe mentions it. As well, when first asked to join Nishiura's lineup, Hanai initially refused, claiming he could never play for a woman; however, soon after, Hanai came around upon Momoe's display of considerable athletic ability.
Hanai is seen having an inferiority complex for Tajima, as he is always the 'second', Tajima beating him in all but height and ability of hitting a homerun. Their relationship is odd if anything, as they cheer for each other as teammates should, but have a rivalry going inbetween. In the latest chapters, it is noticed that Tajima has insecurities too, when Hanai is given the cleanup title in the game against Senda, and later on, more of them add up as Hanai hits a homerun during batting practice, thing which Tajima cannot do even during games, due to his physique.
Along with Coach Momoe , Hanai and Abe work together to analyze data and work on strategies. There are times when Abe teases Hanai, mostly about his bad luck at lottery, like when Abe says to not give up when Hanai is going up for the lottery.
- Hanai is able to play the piano. (Volume 17 Omake)
- He takes 30 minutes to go to school.
- He has "very bad luck" when it comes to drawing lottery. He draws the seeded school (and considered "powerhouse") in the official matches - Tosei, previous year's champions, for Saitama Summer Tournament and Senda, top seeded school (second in the entire Prefecture after ARC), for Saitama Fall Tournament.
- He hates being called 'Azusa' by his mother in public (as Azusa is usually a feminine name), so she compromises by either calling him 'Hanai', or 'Onii-chan'.
- It has been hinted in several scenes that he has a slight crush on Momokan, such as mentally panicking when he realizes that she isn't even a decade older than him and wondering if, 'it was really okay'.
- He mentions that he has a fetish for English teachers.