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.
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.
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.