Seigaku (1st Year)
WILSON (PRO STAFF EX3 Jr.)
Kato Kachiro is a 1st-year at Seishun Academy, and is one of Ryoma's friends and supporters. He is in Class 5 and is usually seen with Mizuno Katsuo and Horio Satoshi. Although he is not very good at tennis, he thoroughly supports the team. He can often be seen cheering for Echizen and the rest of Seigaku at any match. During the monthly Seigaku ranking tournament, Kachiro records Kaido's match for Ryoma, taking a hit in the eye in the process.
Kachiro's father works in a tennis club and offers a free session to Kachiro and his friends. However, Kachiro's father abused by Sasabe, who taunts him for being unable to teach any pro-level skills and for not becoming a pro because of an injury. Kachiro is helpless to help is father, but is relieved when Ryoma humiliates Sasabe.
Though he is normally polite and meek, Kachiro believes strongly in justice and fights to the end to defend his beliefs. As such, he has proven to be brave and stubborn when a situation calls for it. He challenges the 2nd-year Masashi Arai when Arai claims that Seigaku's recent injuries have given him a chance to make the regulars. Despite being outclassed in every way, Kachiro is gradually able to catch up to Arai's shots and make some returns, and persists in playing the game to the end even though losing meant he had to quit the club. The match is stopped by co-captain Oishi, and Kachiro gains a new respect for Arai when he discovers he had been playing with ankle weights on.
- His character placed 20th in the first popularity poll with 306 votes.