Unlike Superman, the Earth-Three Ultraman gets stronger every time he is exposed to kryptonite, originally developing a completely new superpower with each new exposure. In one such encounter, Ultraman acquired the ability to see through dimensional barriers, thus alerting the Crime Syndicate to the existence of alternate Earths in their first appearance. This allowed the Syndicate to attack the Justice League and Justice Society. Ultraman also differed from Superman in that his version of the planet Krypton had not exploded. Where the Earth-Three dimension kryptonite originated was never specifically listed in any published book. However, it is implied to be the same as ordinary kryptonite, as Ultraman got powers when exposed to Kryptonite from pre-Crisis Earth-One and Earth-Two, gaining heat vision from Barry Allen throwing some at him. Being exposed to a large chunk of it paralyzed him, as he acquired so many new superpowers that his body couldn't decide which one to use and he was therefore frozen in place. He does not appear to have been affected after this, so perhaps he can reject powers, or they wear off.
In the early 1980s, Ultraman teamed up with Lex Luthor of Earth-One, and Alexei Luthor of Earth-Two, in an unsuccessful attempt to eliminate the Supermen of both Earth-One and -Two (the Supermen were, in turn, assisted by the heroic Alexander Luthor of Earth-Three). Later, Ultraman joined the rest of the Crime Syndicate in a teamup with a time-traveling villain named Per Degaton who had found their prison and released them. Degaton used them in his attempt to conquer Earth-Two, by stealing nuclear missiles from the Cuban Missile Crisis of Earth Prime, though they planned to betray him. However, this proved unsuccessful as well, and he hurled them into the Future of Earth-1, having made sure this would happen if they touched him, and the events were wiped from the timeline afterwards. The original Ultraman was eliminated in the 1985 12-issue limited series Crisis on Infinite Earths. Distraught at the fact that his superpowers were useless at the one time he actually needed them, he flew straight into the anti-matter cloud that was destroying Earth-Three, telling the Power Ring, "I do what I have done all my life. Fight... to the very end!".
After his death, the Pre-Crisis Ultraman showed up in the pages of Animal Man. There he learned that he was seemingly a comic book character himself, who existed only for the entertainment of others. He also fought Overman, another pre-Crisis alternate universe version of Superman who had been infected by a sexually transmitted disease, became insane and killed, seemingly for the sake of killing. This Ultraman later faded into the mask of the Psycho-Pirate, who, for a time, was the only one who remembered the Pre-Crisis multiverse.
In One Year Later there are hints that a man controlling Kandor, under the name Kal-El, could be Ultraman. He has been using the help of a group of followers called the "Praisesingers" and the guidance of the "Holy Mother". Supergirl and Power Girl fight his efforts, causing his cult-like following to falter. This leader also slays several of his own people to keep political information quiet. It has now been revealed that this Kal-El is indeed Ultraman, who was saved from the Crisis and brainwashed by Saturn Queen, his "mother", one of the masterminds behind the "Absolute Power" arc in Superman/Batman. This version appears to be a much weaker version, as he receives a vicious beating from Supergirl not once, but twice.
An additional incarnation of the Pre-Crisis Earth-Three Ultraman has made appearances most recently in Infinite Crisis where Alexander Luthor, Jr. wanted to create so-called "perfect beings" out of his models of long-dead father Alexander Luthor, Sr., the lone super-hero of Earth-Three, Superman (both of Earth-One and Earth-Two), Wonder Woman (of Earth-One and Two) and the Earth-Three Ultraman and Superwoman.