Jess Mariano is Luke’s seventeen-year-old nephew, the son of his sister Liz. He was introduced in Season Two as a romantic interest for Rory, and as a contrast with her boyfriend Dean. Jess is the “bad boy” that Lorelai feared Rory would be attracted to, in the same way she was when she was a teenager.
Jess is introduced when he steps off the bus, the modern teenage equivalent of the mysterious stranger riding into town. The bus says it is going to Hartford, and Jess boarded it in New York, so Stars Hollow must be on the bus route between these points. In real life, the bus route from New York to Hartford goes through Danbury and Waterbury, which doesn’t seem that implausible as far as Stars Hollow’s possible location goes. The bus trip takes about two and a half hours, and we later learn the bus got in at 10 am.
Jess and Luke greet each monosyllabically by simply saying each other’s names. The mirroring is a sign that Jess and his uncle share at least one characteristic – neither of them are particularly talkative.
There has already been a character named Jess in Gilmore Girls – the college boys that Madeline and Louise got with at The Bangles concert in Season 1 were named Jess and Sean. Maybe Jess seemed like a very “New York bad boy” sort of name? Or the writers really like the name Jess?
Both Rory and Jess have unisex names, or names more common on the opposite sex. It’s interesting that the name Jess Mariano has the same rhythm as Dan Palladino, and they’re obviously both of Italian heritage.