Mc Cord was cast because, according to Sachs, "she's someone who is worldly, and there's a sophistication to her that's interesting." Sachs and Judah had seen Grimes' work before and knew "she had the acting chops", and she was cast after acting a dramatic scene which she "just killed".
The series introduces Annie Wilson (Shenae Grimes) and her adopted brother Dixon (Tristan Wilds), who move from Kansas to Beverly Hills with their father Harry (Rob Estes) and mother Debbie (Lori Loughlin).Sachs explained that Jessica Stroup "came in dressed for the part, artsy and quirky, and she had her hair up and she had a bandana.She nailed it." The producers were fans of Tristan Wilds for his acting on The Wire, and hoped to hire him as Dixon from the start of casting.When that photo is sent throughout her school by Naomi, Annie has a resentment against Mark, but then forgives him.She later agrees to a date with him where there is a confrontation between her and Mark.She and Ethan had dated after he broke up with Naomi, but concealed it so that Naomi would not find out until they were ready to tell her.She does, however, find out when she sees their intimacy in an empty classroom.Sachs found that Walter knew pieces of scenes and suggested "stuff that works".The producers were looking for an actor who could portray Silver as a "quirky kid who moves to her own beat".When the series was cancelled, Sachs called Estes and explained the spin-off and motivated him to participate.Sachs promised that although he was playing a parent, he would not "be furniture..in the seldom seen or heard parents who populate many youth-centric series, like the Walsh parents on the original 90210." Sachs described Tata's casting as an accident; a friend told Sachs that he had seen Tata in a store, which led to the offer of a recurring role in the series.