In Episode 11, Brick is worried about the townspeople's opinions on him dating a woman half his age. He initially breaks up with her, with help from George. However, Brick realizes that it doesn't matter what the town peoples think, and calls her back. (Old Alabama)
In Episode 12, Lemon finds out that Brick has a secret girlfriend and initially believes it to be AnnaBeth, but later finds out that it is Shelby. (Islands in the Stream)
In Episode 14, Brick wants to show Shelby off to the town. Lemon, Magnolia, and Shelby initially set a birthday party for Brick. Shelby decides to jump out of a cake and do a dance number, which Lemon and Magnolia think the act will make Shelby look bad. This is why Magnolia suggests it in the first place to Shelby, but when Magnolia reveals her plan to Lemon - Lemon is upset by Magnolia's actions. The surprise party happens and Shelby goes through with the dance number, which the town likes. (Take Me Home, Country Roads)
In Episode 17, she is slated to appear in We Are Never Ever Getting Back
In season 3, episode 7 it is revealed that Shelby is pregnant and Lemon and Brick suspects it is his.
She had at first told them that she was inseminated, but then later reveled that she had a one night stand with the Lieutenant Governor of Alabama. Then moved with the Lieutenant Governor to his house to raise the baby.