When Jess Mariano (Milo Ventimiglia) is sent to Stars Hollow to live with his uncle, Luke Danes (Scott Patterson), in Gilmore Girls Season 2, he quickly makes enemies. His bad boy attitude and propensity for getting into fistfights with Dean Forrester (Jared Padalecki) makes him a target for tons of vitriol from the townspeople, including Luke.
However, Jess almost immediately connects with Rory Gilmore (Alexis Bledel), and the two embark on a strange, twisting courtship. He makes a ton of mistakes as a teen, especially in his relationship with Rory, but by the time he shows up in Gilmore Girls: A Year in the Life, he's a mature, successful, respected adult. To be frank, Jess' off screen arc is the best in the entire series.
Jess Mariano's Life in Stars Hollow
Jess is sent to Stars Hollow because his mom can't handle his rebellious behavior anymore. He moves in with Luke, who's inclined to give his nephew a second chance -- but when Jess' behavior doesn't improve and it starts to get Luke in the town's crosshairs, he quickly cracks down and forces Jess to clean up his act. That works temporarily, but Luke can't manage to get Jess to go to school -- so his truancy ultimately prevents him from graduating.
Meanwhile, Jess and Rory start dating after months of will-they-won't-they tension (complicated by the fact that she's dating Dean when she and Jess meet) and things are starting to get serious. However, when Jess learns he won't be able to graduate, his insecurities get the best of him and he takes out his anger on Rory, then goes on an ill-advised trip to see his absentee father in California. He doesn't tell Rory he's going, forcing her to figure it out on her own.
Teenage Jess is a well-read but obstinate jerk who only has eyes for Rory. Unfortunately, he makes massive mistakes that damage their relationship permanently.
Jess Mariano Becomes an Author
After his departure in Gilmore Girls Season 3, Jess returns twice in Season 4 and continues to flub things with Rory. In one episode, he tells her he loves her and then takes off; in another, he asks her to run away with him and gets rightfully rejected.
In Season 6, Jess visits Rory when she's staying with her grandparents during a brief and ill-advised sabbatical from Yale University. He reveals he's written a book and joined a publishing house, which is a major change from the last time Rory saw him.
He even confronts her about her out-of-character behavior and encourages her to go home to Stars Hollow and go back to school. When her then-boyfriend, Logan Huntzberger (Matt Czuchry), openly mocks Jess during dinner, Jess displays how much he's matured by not taking the bait -- at least, not in the same way he would have as a teen.
Jess Mariano Grows Up
After his first book is published, Jess' publishing house has an open house event, to which he invites both Luke and Rory. It's clear how hard Jess has worked to get to this point and even though most of that work happens off screen, he's clearly become a responsible, trustworthy person who can handle his share in a blossoming business and focus on his writing.
It's been years since they dated, but Jess still has feelings for Rory. The pair kiss after the open house is over, and she reveals that she only came because she was angry about Logan cheating on her. Jess is appalled at being used, but he also tells Rory she can tell Logan something happened, if it will make her feel better. It's a small, selfless act, but one that speaks volumes about how much Jess has matured -- and how he'll still do anything for Rory, even if they aren't actually together.
Four years later, Jess visits Stars Hollow because his mom and stepdad have been indoctrinated into a vegetable cult. He once again helps Rory find a way forward when she's stuck in a rut and checks in with Luke, who's busy with preparations for his wedding to Lorelai. Throughout his scenes in Gilmore Girls: A Year in the Life, Jess demonstrates his maturity and forces these people he loves to actually examine their behavior and act in their own best interests.
Jess' journey on Gilmore Girls is long and often painful, but it's also one of the most satisfying. He grows up, learns from his mistakes, follows his passion and makes himself proud, thereby also proving himself to the people who helped him get to that point. So much of his story happens off screen, which leaves plenty of room for fans to imagine the exact events that take Jess from being a rebellious teen to a successful adult.