Set inMilwaukee, Wisconsin, the series revolves aroundteenagerRichie Cunninghamand his family: his father, Howard, who owns a hardware store; traditional homemaker and mother, Marion; younger sisterJoanie; Richie's older brother Chuck (briefly in seasons 1 and 2 only); and high school dropout, biker and suave ladies' manArthur "Fonzie"/"The Fonz" Fonzarelli, who would eventually become Richie's best friend and the Cunninghams' over-the-garage tenant. The earlier episodes revolve around Richie and his friends,Potsie WeberandRalph Malph, with Fonzie as a secondary character. However, as the series progressed, Fonzie proved to be a favorite with viewers, and soon more story lines were written to reflect his growing popularity; Winkler eventually received top billing in the opening credits alongside Howard.Fonzie befriended Richie and the Cunningham family, and when Richie left the series for military service, Fonzie became the central figure of the show, with Winkler receiving sole top billing. In later seasons, other characters were introduced including Fonzie's young cousin,Charles "Chachi" Arcola, who became a love interest for Joanie Cunningham. The eleven seasons of the series roughly track the eleven years from 1955 to 1965 in which the show was set.