Pilot Episode: The pilot for "Happy Days" was actually an episode of "Love, American Style" titled "Love and the Television Set," later retitled "Love and the Happy Days" for syndication, which aired in 1972.
Inspiration: The show was inspired by the success of the film "American Graffiti," which also starred Ron Howard, who went on to play Richie Cunningham.
Theme Song Switch: For the first two seasons, "Happy Days" used "Rock Around the Clock" by Bill Haley & His Comets as its theme song.
The Fonz's Leather Jacket: Initially, network executives didn't want Fonzie (played by Henry Winkler) to wear a leather jacket, fearing it would make him look like a thug.
Spin-offs: "Happy Days" led to several spin-offs, including "Laverne & Shirley," "Mork & Mindy," and "Joanie Loves Chachi."
Live Audience: The show began filming without a live audience and used a laugh track. Starting with Season 3, it transitioned to being filmed in front of a live audience, which added to the energy and timing of the comedy.
The Phrase "Jump the Shark": The phrase "jump the shark," used to describe the moment when a TV show starts to decline in quality, originated from an episode in which Fonzie literally jumps over a shark while water skiing.
Ron Howard's Departure: Ron Howard left the show after the seventh season to pursue a career in directing.
Fonzie's Full Name: Fonzie's full name is Arthur Fonzarelli. His nickname, "The Fonz," became an iconic part of American pop culture.
Set Recycling: The set used for Arnold's Drive-In, a central location in the series, was later reused in the 1978 film "Grease" for the Frosty Palace scenes.