Who is Joichi 'John' Ueno from My Year of Meats and what is their importance?

Joichi 'John' Ueno is an ad executive who represents BEEF-EX, the beef industry organization for whom Ueno's agency produces My American Wife! Upon Ueno's first visit to America to supervise the show, Jane gives him the nickname of John in order to throw him off balance. Instead, John embraces the name. John is a huge fan of everything American, especially big bossomed Texas women.