Louisa Arcola (later Louisa Arcola-Delvecchio) appeared as a recurring character in a total of five episodes of Happy Days from Season 8 to Season 11; she reprised the role in its spinoff, Joanie Loves Chachi as a main character, the mother of Chachi as well as the aunt of Fonzie, and later, the new wife of Al Delvecchio. The part of Louisa was played on both series by Ellen Travolta.
About Louisa
In the spinoff series Joanie Loves Chachi, newlyweds Al and Louisa move to Chicago from Milwaukee and open a family restaurant, as Chachi accompanies the two. Joanie spends the summer in Chicago to be with Chachi and, eventually, moves there to attend Northwestern University.