Creator/producer "Eiji Tsuburaya" intended "Ultra Seven" to be the final Ultra Series. It was indeed the last Ultra Series to be supervised by Eiji. But because of the series' success, Tsuburaya Productions started on a story draft in late 1969 titled "Zoku Urutoraman" ("Ultraman Continues"), which was a direct sequel to the original Ultraman: A Special Effects Fantasy Series (1966) (In it, the characters from the original series would return, and Hayata, once again played by "Susumu Kurobe" , would find a successor to the Beta Capsule). But Eiji had passed away early the following year. The proposed story was ultimately reworked into Ultraman Returns (1971), although Tsuburaya was also going to use it again in 1988 (during the then-popular Ultraman boom).
Originally, "Ultra Seven" was not going to be related to the original Ultraman: A Special Effects Fantasy Series (1966) TV series, but was intended as an alternate version. Initially, months before that series ended production, Tsuburaya Productions pitched to Tokyo Broadcasting System (TBS) an idea for a new sci-fi adventure called "The Ultra Garrison" ("Urutora Keibitai"). The project then evolved into "Ultra Eye" ("Urutora Ai") about Dan Moroboshi, an esper alien from Planet R. He was born to an alien father and a human mother, whom he went to Earth in search for. Upon coming to Earth, Dan joined the Ultra Garrison, and became the driver of the Garrison's Supercar. But unbeknownst to anyone, in times of crisis, Dan transforms into his R-ian form, known on Earth as Redman. Almost identical to Ultra Seven, Redman's Capsule Monsters were to be monsters that were originally from Urutora Q (1965) and "Ultraman" (Red King, Antlar and Peguila). With several changes to the plot (including the hero's homeworld being the Land of Light in the Nebula M78, just like Ultraman), the show began production as "Redman" ("Reddoman"), the same working title that "Ultraman" had used. Casting auditions were held in June. Episodes 3, 2, 6 and 4, in that order, were produced in May of 1967. Just before Episode 1 next began production, the series title was ultimately changed to "Ultra Seven," with Episode 1 being the first to bear that title. All references to Redman in previous episodes were dubbed out. Post-production was completed in September, and the show finally premiered on October 1, 1967, competing with Johnny Sokko and His Flying Robot (1967) and Kaijû Ôji (1967), and earning a 30% rating.
Considered by Japanese fans to be not only the most popular entry of the Ultra Series, but also one of Japan's greatest sci-fi/superhero TV shows. Due to his huge popularity, the character of Ultra Seven (as well as his alter-ego, Dan Moroboshi, played by Kôji Moritsugu) has appeared in more sequels and spin-offs than any other character in the Ultra Series.
The concept for Dan Moroboshi/Ultra Seven's "Capsule Monsters" (capsules that explode and become giant monsters, and back again upon Dan's command) became the inspiration for Bulma's exploding convenience capsules in _"Doragon bôru" (1986)_ and for the PokeBalls in the hit video game/TV series, Pokémon (1997). (The creators of both shows, Akira Toriyama and Satoshi Tajiri respectively, were big fans of this series.)
This was the first English-dubbed Japanese TV series in Hawaii (in 1975). Produced by Tsuburaya's Hawaii branch, it was dubbed by the Commercial Recording Company in Honolulu, and the voice talent consisted of several students from the Speech Department of the University of Hawaii.