Over 1,500 girls auditioned to replace Eve Plumb as Jan Brady. The two finalists were Kathy Hilton (mother of Paris Hilton) and Geri Reischl, who won the part.
Eve Plumb's father wanted her to have limited involvement in the show. She agreed to do the pilot plus five episodes, but the network insisted on a 13-episode contract with a five-year option.
Most of the cast was prepared for weekly song-and-dance routines. The kids had practiced choreography on-set during the original show's run, and put on concerts between seasons. Florence Henderson had sung professionally. Robert Reed tried hard, but according to Henderson, "Bob had two left feet!" His choreography was kept to a minimum.
Maureen McCormick (Marcia) had become bulimic and developed addictions to cocaine and Quaaludes, which caused mysterious bruises on her arms and legs and made her behavior erratic. She began calling in sick, arriving late to rehearsals, refusing to come out of her dressing room, showed up for work at the end of a 72-hour bender, and once completely missed the taping of the majority of an episode. Gradually, Geri Reischl (Jan) began having to learn McCormick's part in addition to her own so she could take over a scene if McCormick didn't show up.
Christopher Knight had quit The Brady Kids singing group a few years earlier, feeling that he was tone-deaf and had no skills as a dancer. When this show was proposed, he had no intention of doing it but, with the absence of Eve Plumb, the producers were desperate to reassemble the rest of the cast, so they promised that Knight's musical performances would be relegated only to the opening and closing numbers. They lied.