Jessica is a young vampire and the progeny of Bill Compton. Bill was forced to turn her as punishment for staking another vampire (which by vampire law is illegal).
Jessica embraces being a Vampire and was never really depressed about being turned into one. She was brought up in a strict, abusive Christian household, so she enjoys being able to curse, dress inappropriately and do things at her leisure.
In the second season, Jessica meets and begins a relationship with Hoyt Fortenberry. Unfortunately, since she was a virgin before she was turned, her hymen will always heal itself. However, Hoyt loves her the way she is and accepts her, unlike his hateful mother who despises her. At the end of the second season the two break-up because of Hoyt's mother, but get back together by the end of the third season and move in together.
In the fourth season, which jumps a year ahead, Jessica and Hoyt are still living together, but the relationship is obviously strained. After he rescues her from nearly "meeting the sun" Jessica kisses Jason Stackhouse (Hoyt's best friend) and decides to break up with Hoyt in favor of him. However, Hoyt breaks up with Jessica first and goes on a vampire-hating rampage and drinking binge. When Hoyt sends Jason over to Bill's place with Jessica's stuff, she and Jason have sex in the back of his truck. Jason eventually tells Hoyt, which causes him to hate both Jessica and Jason. Jessica and Jason begin a sexual relationship.
In the fifth season, Jessica and Jason continue to be friends and occasionally have sex. In the meantime, Hoyt tries to win Jessica back to which she rejects him. He then joins a vampire hate group that captures Jessica and nearly kills her, however Hoyt lets her go because he still loves her. Unable to bear Jessica and Jason's betrayal any longer, Hoyt begs Jessica to glamour him into forgetting her and Jason entirely. She tearfully complies and Hoyt leaves for Alaska.
Later in the season, Bill has begun to go crazy after becoming a member of the now corrupt Vampire Authority. Bill forces Jessica to live in the Authority headquarters where she cannot leave and has to bend to any command Bill makes. At the end of the season, Jessica is assisting Pam, Tara, Jason, Nora, Eric and Sookie in infiltrating the Authority. She professes her love for Jason, but Jason being under a kind of stupor, rejects her because she is a vampire.