While on a business trip to Japan, Haim Saban discovered the Super Sentai series Choudenshi Bioman on TV Asahi and a popular French-language dub on Canal+, which inspired him to pursue an American adaptation. He and Shuki Levy produced an early pilot called Bio-Man in August 1986, starring martial artist Mark Dacascos, but were unable to sell it for five years.
Saban finally found success in 1992 through Fox Kids executive Margaret Loesch, who was familiar with Super Sentai after seeing Stan Lee try to sell the Sun Vulcan series to networks during her time at Marvel Productions. The pitch, using footage from Kyōryū Sentai Zyuranger, was initially titled Galaxy Rangers before becoming Mighty Morphin Power Rangers.
Many of the lead actors were cast for their athletic backgrounds: Amy Jo Johnson (Kimberly) and David Yost (Billy) were former competitive gymnasts, Austin St. John (Jason) held black belts in Taekwondo and Judo, Walter Emanuel Jones (Zack) was a trained dancer and Taekwondo practitioner, and Thuy Trang (Trini) was a kung fu practitioner.
Jason Narvy, who played the bully Skull, originally auditioned for the role of Billy Cranston.
The series was filmed on location in Santa Clarita and Los Angeles, and the exterior of the Command Center was shot at the House of the Book at the Brandeis-Bardin Institute, a building previously used in Star Trek VI: The Undiscovered Country and The Lawnmower Man.
As part of the licensing deal with Toei, additional footage of the villain actors (such as Machiko Soga, Ami Kawai, and Hideaki Kusaka) was filmed in Japan, including close-ups of them mouthing English dialogue phonetically to make dubbing more seamless.
Episodes 39 and 40 were originally meant to be the series finale, but Fox Kids ordered 20 additional episodes due to the show's massive success. Since the available Zyuranger stock footage had run out, Saban commissioned Toei to build 25 new monster costumes and shoot new battle footage, known among fans as 'Zyu2'.
When the Thunderzords were introduced early in Season 2, they actually came from Gosei Sentai Dairanger rather than Zyuranger, forcing Saban to splice together footage from both 'Zyu2' and Dairanger for the Megazord battle scenes.
After Austin St. John, Thuy Trang, and Walter Emanuel Jones left the show over contract disputes partway through Season 2, body doubles, voice doubles, and stock footage were used to keep their characters appearing for eight more episodes, with the in-story departure explained as the characters attending a World Peace Conference.
During the latter part of Season 2, production relocated to Sydney, Australia for about four months to film Mighty Morphin Power Rangers: The Movie, which was released the following summer before Season 3 began.
Within three weeks of its 1993 premiere, Mighty Morphin Power Rangers became the top-rated children's television series in the United States, capturing 45% of the viewing audience aged six to eleven and reaching ratings not seen since Teenage Mutant Ninja Turtles two years earlier.
The show's violent content led to significant controversy: Canada's YTV pulled it from its lineup in 1993 after complaints to the Canadian Broadcast Standards Council, and New Zealand's Broadcasting Standards Authority upheld complaints in 1994, leading Television New Zealand to cancel the second season, making New Zealand the only country to have prematurely pulled the show from broadcast.
In mid-October 1994, Swedish-owned TV3 pulled the show from broadcast in its market countries following the murder of Silje Redergård by two young friends, even though the show was not actually related to the event.
As a non-union production, the original cast reportedly faced low pay of about $60,000 per year with no merchandising royalties, despite the franchise being worth an estimated $1 billion; Austin St. John stated he could have made the same money working at McDonald's.
David Yost, who played Billy, left the series citing homophobic attitudes from production staff, including being called slurs on set, which led him to undergo unsuccessful conversion therapy; a producer later disputed this account, claiming Yost left over a pay dispute.
The Tenga Warriors, crow-like soldiers introduced in Season 3, originated in Mighty Morphin Power Rangers: The Movie under the name 'Tengu Warriors' commanded by Ivan Ooze, but were renamed due to copyright issues with the movie's producer, 20th Century Fox.
In Malaysia, the series was broadcast simply as Power Rangers because the word 'Morphin' was considered too similar to the name of the drug morphine.
