The family consists of Howard Cunningham, a hardware store owner, his homemaker wife Marion and the couple's two children, Richie, an optimistic if somewhat naive teenager, and Joanie, Ritchie's sweet but feisty younger sister. The Cunninghams also had an older son named Chuck, a character who disappeared during the second season.
The earlier episodes revolve around Richie and his friends, Potsie Weber, Ralph Malph and local dropout Arthur "The Fonz" Fonzarelli, but as the series progressed, "Fonzie" proved to be a favorite with viewers and soon more story lines were written to reflect his growing popularity. Soon Fonzie befriended Richie and the Cunningham family. The focus would also occasionally shift to other additional characters, such as Fonzie's cousin Chachi, who became a love interest for Joanie Cunningham.