Several years have passed since the events of Ultraman, with the legendary "Giant of Light" (光の巨人,Hikari no Kyojin?) now a memory, as it is believed he returned home after fighting the many giant aliens that invaded the Earth. Shin Hayata's son Shinjiro seems to possess a strange ability, and it is this ability, along with his father's revelation that he was Ultraman, that leads Shinjiro to battle the new aliens invading the Earth as the new Ultraman.
Shinjiro Hayata (早田 進次郎（ハヤタ・シンジロウ）,Hayata Shinjirō)
The protagonist. When Shinjiro was born, he was seen to possess a strange "Ultraman Factor" (ウルトラマン因子,Urutoraman Inshi) that makes him superhuman, with his mere grasp able to break bones and his leap allowing him to span buildings. When aliens begin invading Earth, Shin Hayata and Dr. Ide give Shinjiro a special Ultraman Suit (ウルトラマンスーツ,Urutoraman Sūtsu) to battle the monsters invading the Earth.
Shin Hayata (早田 進（ハヤタ・シン）,Hayata Shin)
Shinjiro's father and the original Ultraman. At the beginning of the story, he has been given the title of Minister of Defense. Although the Ultraman entity has left his body, and he only has vague memories of his time as Ultraman, he still possesses some Ultraman Factor within him that allows him to fight to some extent, but he returns to the sidelines after being hurt in the battle with Be Mular.
Mitsuhiro Ide (井手 光弘（イデ・ミツヒロ）,Ide Mitsuhiro)
A former member of the Japan Branch of the Science Special Search Party (科学特捜隊,Kagaku Tokusō-tai), and now chief of the Institute of Science and Technology (科学技術研究所,Kagaku Gijutsu Kenkyūsho). He secretly has known that Shin has recently transformed into Ultraman to fight monsters, revealing this fact to his friend at the Giant of Light Memorial (光の巨人記念館,Hikari no Kyojin Kinenkan), the secret base of the Science Special Search Party. He gives Shinjiro the Ultraman Suit and reveals the truth about his father to him. Although he usually appears stoic, he is angered by the Alien Adasic's actions.
Dan Moroboshi (諸星 弾（モロボシ・ダン）,Moroboshi Dan)
A mysterious man who works with the Science Special Search Team, but only seems to appear at the scenes of murders which an alien is the culprit. He feels that Shinjiro is too immature for the responsibilities placed on him as the new Ultraman. Moroboshi shares his name with the main character of Ultra Seven, and is able to use a battle armor similar to Shinjiro's which looks like Ultraseven.
Akiko Fuji (富士 明子（フジ・アキコ）,Fuji Akiko)
A former member of the Science Special Search Team with Hayata and Ide, but is now Moroboshi's superior officer.
An alien who appears in shadow to Shinjiro, allegedly in an attempt to bring the Earth into the Stellar Cluster Council. He also claims to be the first enemy, but his true reasons for his actions are unknown. He is named after the Ultraman monster Bemular.
Ed, the Zetton Alien (ゼットン星人・エド,Zetton Seijin Edo)
The last of the Zettonian race, Ultraman's fierce enemies in the past. This time, he assists the Science Special Search Party in their fight against the other more dangerous alien species, providing them with the technology of the Ultraman Suits.
Adacic Alien (エイダシク星人,Eidashiku Seijin)
A mysterious alien hiding as a human on Earth, preying upon people in the guise of a serial killer, and one of Shinjiro's first foes as Ultraman. He resembles the Baltan Aliens, which were designed after the Cicada Man from Ultra Q.
Igaru Alien (イガル星人,Igaru Seijin)
A short alien that stalks the popular idol Rena Sayama.
A resident of the Alien City who is a popular boxer, but has recently been dethroned by Jack. He resembles the monster Red King.
A police officer who unwittingly is drawn into the world of aliens living on the Earth during his investigations. His daughter is a huge fan of the original Ultraman.
Endo's junior partner.
Rena Sayama (佐山 レナ,Sayama Rena)
A popular idol around Shinjiro's age. She is a fan of both the original and the new Ultraman, dedicating her third single "Ultlove" (ウルトラブ,Urutorabu) to him. She has seemingly fallen in love with the new Ultraman, unaware that he is Shinjiro.
A human who lives in the Alien City who possesses powers rivalling that of the resident extraterrestrials, even winning in a boxing match against Red. He acts as an informant to Moroboshi. His real name is unknown. He seems to possess a bracelet that resembles the Ultra Bracelet used by Hideki Gō when he become Ultraman Jack in The Return of Ultraman.