Very little is known about Diego’s background, although he appeared to be a very popular kid at his high-school, and Penny Carson had a crush on him. The two lived in the same neighborhood and Penny claims they have a “thing” where they say “hey” to each other.
Penny is able to overcome her shyness around him and asks him to senior prom, but he rejects her and chooses to go to prom with Layla K., a turtle girl, over her. He is the catalyst for Penny's disastrous prom night leading her to ask BoJack to sleep with her after being rejected.
Very little is known about Diego’s personality, although from what has been said about him he seems to be cool with a mellow personality, but not standoffish. His caption in the school yearbook reads "Biggest Flirt".
Diego is a young man in high-school with dark brown hair, a slightly muscular build, and stubble on his chin and under his nose.
He is shown at prom wearing a maroon tuxedo, a pink flower corsage, a dark purple button down vest, a bow-tie, a white collared shirt, and dress shoes.