The series revolves around teenager Richie Cunningham and his family.
Other actors are:
- Marion "Mrs. C" Cunningham: wife of Howard Cunningham, mother of Richie and Joanie, and a traditional homemaker;
- Howard "Mr. C" Cunningham: husband of Marion Cunningham, father of Richie and Joanie, business owner of a hardware store called "Cunningham's Hardware", he is a lodge member, and family man;
- Joanie Cunningham: Richie's younger sister;
- Arthur Herbert "Fonzie" Fonzarelli: initially a minor character, he was a hugely popular heart-breaker;
- Warren "Potsie" Weber: Richie's best friend and an aspiring talented singer;
- Ralph Malph: in the first season, he was more of a side character to plots. He is know for saying "I still got it!" after delivering one of his jokes;
- Charles "Chachi" Arcola: Fonzie's younger cousin;
- Al Delvecchio: From seasons four to nine, he became the new owner/cook of the drive-in after Arnold got married the previous season. He is know for sighing "Yeeep, yep, yep, yep, yep" when he was disappointed or when things did not go his way;
- Jenny Piccalo: Joanie's boy-crazy best friend;
- Roger Phillips: Marion's nephew, coach and teacher at Jefferson High;
- Lori Beth Allen-Cunningham: Richie's girlfriend and later his wife;
- Ashley Pfister: divorced mother who becomes Fonzie's steady girlfriend.
The first two seasons of Happy Days were filmed using a single-camera setup and laugh track. The show had two main sets: the Cunningham home and Arnold's/Al's Drive-in, the meeting-place.