Gary Concord Sr., a 20th-century scientist, was put into suspended animation in 1950 to awake to find his long sleep had given him super powers and he was in the year 2174.
He put his new abilities to work defeating the tyrant Rebborizan, the people came to call him the Ultra-Man, and he married Leandra, the daughter of the dictator he had defeated.
His son Gary Concord Jr. was born in 2214 and inherited his abilities and grew up to be the second Ultra-Man as well as the High Moderator of the United States of North America. (which extended from Canada to Brazil.)
Gary Concord Jr. battled the warlord Tor and other menaces until he, like his father, was put into suspended animation until the 100th century where the traveled to the planet Almeer-5 and formed a super team made up of himself and three others called Avatar, Behemoth and Metallica (not to be confused with the film by James Cameron, the beast from the Bible or the heavy metal band.)
While this character has the same name and super name as the Silver-Age Ultraman of Earth-3 and other incarnations and both are from DC they are otherwise unconnected.