Superboy-Prime, formerly known as Superman-Prime, whose real name is Clark Kent, is the version of Superman native to Earth-Prime. On his earth, all the familiar superheroes of the DC Universe are comic book characters, and Clark seems to be the only real one. He was in love with his friend Laurie.
Clark Kent grew up being made fun of for sharing a name with the comic book character, Superman. His world had no versions of Superman's friends, however.
Clark developed a strong friendship with Lori, and had romantic interest in her, but was too shy to act on it. Once she got a boyfriend, their friendship was strained. Clark eventually learned he actually had powers, just like Superman, his favorite comic book hero. It was then that he encountered the Superman of Earth-1.
Crisis on Infinite Earths
Enraged at the unfairness of his situation, he broke out of the paradise dimension into New Earth, and enacted a plan to destroy this Earth, which he considered flawed, in an attempt to bring his Earth back.
After a final confrontation with two Supermen on Mogo, he was locked away by the Green Lanterns inside a red star, rendering him powerless. He was guarded at all times by 50 Green Lanterns.
Sinestro Corps War
The Sinestro Corps rescued Prime from his imprisonment, and he joined their corps, fighting against the Green Lanterns. He engaged the new Ion in personal combat and won.
However, he was injured by a Guardian of the Universe who sacrificed himself to stop Prime. This sent the boy through the barrier between dimensions.
He finally truly became Superman-Prime, as his body was aged somehow. Having been sent out of our universe by a Guardian, he began searching the Multiverse for his own Earth.
He viciously destroyed entire worlds in his search for his own.
Legion of Three Worlds
In the miniseries Final Crisis: Legion of Three Worlds, Superboy-Prime found his way into the future. There, he explored the Superman museum, where his tour guide was a holographic version of Jimmy Olsen. There, he learned that he had an insignificant place in Superman's history. This inspired him to join the Legion of Super-Villains.
When the Legion of Superheroes summoned Superman from the past, he helped them fight the opposing legion, and hoped to redeem Superboy-prime. The legion also brought in two alternate versions of the Legion of Superheroes from other dimensions.