"'Fonzie Moves In'" is the first episode of the third season of Happy Days; it was also the 40th episode aired in the series overall. The episode was written by Lowell Ganz and Mark Rothman, and directed by Jerry Paris. It originally aired on ABC on September 9, 1975.
Howard's hardware store begins facing competition. Now increasingly concerned about finances, Howard decides to rent the room above the family garage to generate some extra income. He looks around for a suitable tenant, but becomes aghast when Richie rents it to Fonzie. Howard is certain that Fonzie's unsuitable and plans to evict him.
Due to slow business at the hardware store, Howard decides to rent out the adjoining upstairs attic/apartment as a way to make more money. Fonzie brings his grandmother, Grandma Nussbaum (Lillian Bronson) over to rent it but she hates it. While his dad helps her down the outside steps,Richie talks Fonzie into moving in instead, much to the horror of Howard who still considers Fonzie a "hood" and nothing but trouble. (He nearly chokes Richie!) Will these two very different backgrounds be able to co-exist?
Fonzie breaks the record on the pinball machine at Arnold's as his grandmother watches. Fonzie and his grandmother leave on his motorcycle. Joanie comes into Arnold's and announces that Howard has a big announcement to make. Howard announces that Fryfeld's Fish Market is going out of business, and a new hardware store (Hardware Village) is going to open up across the street from Cunningham Hardware.
Richie and Marion consider getting jobs (Marion suggests she go back to be a secretary), and Marion has the idea of renting out the room over the garage (the attic; which has its own entrance, electricity, and bathroom). Arnold's gets a new pinball machine and Richie suggests that Fonzie's grandmother. Grandma Nussbaum, visit the room for rent.
Mrs. Nussbaum checks out the room (they are asking $50 a month) and Richie suggests Fonzie take it while his grandmother takes his apartment. Howard nearly chokes Richie when he hears the news. Fonzie gives 3 month's rent in advance, and Howard relents and gives him a one-week tryout.
Fonzie then moves in. Howard learns that Hardware Village isn't going to open up and is being replace by a bowling alley. The Cunninghams think there is a fire in Fonzie's room, but Fonzie's girlfriend (Vivian) is cooking an egg on the stove. Howard tells Fonzie he is one of the family and would hate to see him leave, and Fonzie agrees to stay.
- As of this episode, Happy Days permanently switched from a single-camera setup to a multi-camera setup with a live studio audience. To accommodate, the main sets were rebuilt - most notably the interior of the Cunningham house. Also, Fonzie's catchphrase "Sit on it" and his nickname for Joanie, "Shortcake," are first spoken.
- Starting with this episode, Bill Haley and the Comets "Rock Around the Clock" is no longer heard, and is replaced with Norman Gimbel and Charles Fox's "Happy Days" for both the opening and closing credits.
- Ron Howard as Richie Cunningham
- Henry Winkler as Arthur "Fonzie" Fonzarelli
- Tom Bosley as Howard Cunningham
- Marion Ross as Marion Cunningham
- Anson Williams as Potsie Weber
- Erin Moran as Joanie Cunningham
- Don Most as Ralph Malph