He first appeared in Captain Tsubasa manga. He's a retired Japanese footballer and is an employee, primarily a talent scout of the Japan Football Association (JFA). According to World Youth Cup he comes from a very rich family, but broke ties with them for years when he chose soccer over joining the family enterprise.

Katagiri pulls the strings in the background and supports the many talents of the Golden Age, including Tsubasa, Misaki, Hyuga, Aoi, and many others, on their way to the top of the world. In the film series and the U-13 International Tournament arc, Katagiri has also being assistant coach and in charge of helping U-13 Japan, U-14 Japan and All Japan Jr. in their matches against European teams and in the Jr. World Cup in Film 4. As JFA representative, he continues to support the Golden Generation: he agreed in Battle of World Youth to have a shadow team called Real Japan 7 to make the All Japan Youth stronger and be prepared for the 2nd Asian preliminaries. He arranged to have the U-20 International World Youth Cup in Japan in little time with the assistance of his father, Mr. Katagiri, who is an important corporate businessman in Japan. This was not without trouble, since Katagiri Sr. at first asked in exchange for him to drop all his ties to the Japan Team and return to the clan; when Katagiri Jr. said he'd look for help elsewhere rather than bow to his father's demands, said father softened up and said he'd help the team anyway, only asking his son to visit his mother.

(Source: Captain Tsubasa Wiki)