Mork first appeared in the Happy Days season five episode "My Favorite Orkan," a riff on the 1960s sitcom My Favorite Martian, created because producers wanted a spaceman character to capitalize on the popularity of the recently released Star Wars.

Actor-director Jerry Paris was inspired to create Mork after directing a Dick Van Dyke Show episode called "It May Look Like a Walnut," written by Carl Reiner, in which Rob Petrie dreams that alien walnut-people have invaded Earth.

Dom DeLuise and Roger Rees were both offered the role of Mork but turned it down, and Richard Lewis and Jeff Altman were also considered before Robin Williams was cast.

At his audition, Robin Williams was asked to take a seat and instead sat on his head, which so impressed producer Garry Marshall that he cast him on the spot, later joking that Williams was the only alien who auditioned.

Because the original Happy Days episode ended with Mork's visit revealed as just Richie's dream, an extra scene was later filmed and added to the syndicated version showing Mork erasing everyone's memory, in order to set up Mork & Mindy as a spin-off.

Scripts for Mork & Mindy were shorter than those for Happy Days, with directions simply noting "Robin will do something here" to allow Williams to improvise on set.

Williams's genuine improvised ad-libs were often too unsuitable for general television audiences, so a large writing team had to script replacement "ad libs" that merely sounded improvised.

For the fourth season, Jonathan Winters, one of Robin Williams's idols, joined the cast as Mork and Mindy's child Mearth, who due to Orkan physiology hatched from an egg as a full-grown adult since Orkans age backward.

The show's ratings peaked at number 3 in its first season but collapsed after being moved to Sundays for season two as a counterprogramming move against NBC's Sunday Big Event and CBS's Archie Bunker's Place, dropping the show to 27th place.

The house used for Mindy's residence is a real home located at 1619 Pine Street in Boulder, Colorado, which was later also used as a filming location for episodes of Perfect Strangers and Family Matters.

Mork's greeting gesture, "Na-Nu Na-Nu," combined a handshake with a hand gesture resembling Mr. Spock's Vulcan salute from Star Trek.