This was the first Ultra Series to link all previous Ultra Series together. Both Ultraman: A Special Effects Fantasy Series (1966) and Ultraseven (1967) took place in completely different continuities. (The first series took place in 1993, and the latter in 1987.) This series is set in the Present, retroactively putting all previous series in the past.
Considered by many to be the best of the 70s Ultra Series.
This series was originally based on a 1969 story treatment commissioned by Eiji Tsuburaya, titled "Zoku Urutoraman" ("Ultraman Continues"), which was planned as a direct sequel to the original Ultraman: A Special Effects Fantasy Series (1966). In it, all of the original cast members would return to reprise their roles, and Hayata ('Susumu Kurobe') would find and mentor a successor to the Beta Capsule. Unfortunately, Eiji Tsuburaya passed away before production began. Eventually, the story was retooled into this series, with an all-new Ultraman, and an all new human host (Hideki Go).
The first Ultra Series where the first episode was filmed first. (All previous series had the episodes shot out of sequence.)
The official name for the Ultraman in this series is "New Ultraman" ("Shin Urutoraman"). But in the late 1970s, Bandai (which had since become the licensor for Ultraman toys in Japan) held a survey for children, and Tsuburaya gave him his current official licensing name, "Ultraman Jack" ("Urutoraman Jakku"). He is still occasionally called New Ultraman, however.