The Ultimen themselves are a pastiche of several superheroes from the Super Friends, who were added during the season titled Challenge of the Super Friends in order to add ethnic diversity to the lineup, as well as the Wonder Twins. These characters were all created specifically for the series and had not previously appeared in any comic books. While the Ultimen retain the powers and cultural backgrounds of these characters, they are portrayed in a far less stereotypical fashion. Additionally, the two characters based on the Wonder Twins do not need to touch hands to transform, unlike the Super Friends originals.
First appearing in the episode "Ultimatum", the Ultimen assisted the Justice League in saving an off-shore oil platform from a group of lava monsters. Near the end of the fight, Wind Dragon created a cyclone of arctic wind that froze the remaining creatures solid, a power he had never displayed before. Concerned, but not willing to dwell on it, he turned his attention to the media, giving such a heartwarming speech that it even made the infamously wholesome Superman groan. Though they were given the chance to join the Justice League, the Ultimen declined, saying they did not feel worthy yet for membership.
The team's money manager, Maxwell Lord, used the media to make them look like selfless heroes who had nothing to hide from the public. He contested that his Ultimen, unlike the Justice League, were a group of "down-to-earth" heroes (both figuratively and literally) to whom the people could relate. Lord also justified the use of marketing their images and likenesses through toys and merchandise as a way to fund their crime fighting careers, giving the members generous royalty checks to buttress his argument. Secretly, however, he was growing concerned with the knowledge that Wind Dragon had gained a new power, and called all the Ultimen together for testing. Long Shadow, having also mutated into gaining super hearing, heard Lord speaking to their doctor, Professor Hamilton, and learned that the Ultimen themselves were actually created in a lab and implanted with false memories by members of Project Cadmus. Eventually, they interrogated Lord and forced him to tell them that they were dying and were going to be replaced by clones. Angry, the Ultimen attempted to find the woman in charge, Amanda Waller, but she and her project were long gone on her orders. When the Justice League showed up, they stopped searching for Waller and (except for Long Shadow) attacked them in hopes that they would be remembered for defeating the world's most powerful heroes. They eventually lost, and with the exception of Long Shadow (who was officially offered membership into the Justice League), were taken into Cadmus' custody to await their eventual deaths. None of these original Ultimen make additional appearances in the series, and it is likely that their bodies simply deteriorated upon death.
In the episode "Flashpoint", it is revealed that Cadmus has created an army of clones of all the Ultimen, to be led by Galatea (herself a clone of Supergirl) against the Justice League. This Ultimen army no longer have the personality of the originals and are, basically mindless automatons controlled by Galatea. In the following episode "Panic in the Sky", the clone army attacks the Justice League's Watchtower while its founding members are being held on Earth. The remaining members of the Justice League defeat them and Galatea, though it was not revealed how or even if they were disposed of afterward.