In the pilot, Jesse is revealed to be the guy that Amy is dating. He's Ashley Stanton's brother and Val Stanton's son. He gets in a fight with Ty at a party while he is drunk, and isn't seen again until later on in the show. Amy breaks up with Jesse after this.
In Season 8, Jesse talks to Caleb about business. They become business partners, but it is a plot to get back at Ty. Since Ty lives on land that Caleb owns when Caleb goes bankrupt, Jesse takes the land. Jesse provokes a fight with Ty in order to press assault charges against him. This would ruin Ty's chances of becoming a vet and marrying Amy. The charges are eventually dropped due to the intervention of Val.
Jesse has a very snobbish and immature attitude. When things don't go his way, he seeks revenge.