In his first scene, Charlie makes an impression on Annie with his literary name-checking and low tolerance for superficiality. In "Age of Inheritance", it was revealed he is Liam's half-brother. They previously had a falling out because Charlie stole some credit cards from their uncle in Minnesota and blamed it on Liam.
He and Anniestart dating but Annie ends up sleeping with Liam. After talking to Liam properly, Charlie tells him that he only let Liam get beat once by their uncle, but Charlie got beaten almost every day. He also tells Liam he wanted to protect him, not hurt him. With that said, Liam reconciles with Charlie.
However, after Charlie finds out that Annie and Liam slept together during the episode "Holiday Madness ", he leaves to go to Paris for a semester abroad. He lets Liam stay in the house and helps his brother and Annie finally get together. Annie cheats on Charlie with Liam and still lies to him for about 2 episodes.