Superman (Earth-One)

Sent to the planet Earth while only an infant because of the impending destruction of his home planet, the "Last Son of Krypton" became one of the Earth's most powerful and publicly acclaimed superheroes.

The Riddler's Magnificient Seven
Tired of being constantly defeated by Batman and his sidekicks, the Riddler decided to get together a band of fellow criminals (seven in total, hence the name of the group) to go take out Superman, whose power he grossly underestimated. The other members of his group included Catwoman, Killer Moth, Scarecrow, Gathit, Mr. Freeze, and Jonah Hex. When the group finally arrived in Metropolis after a long trek on a stagecoach, Superman easily defeated them despite the Riddler's elaborate plan to take him down.

Forming the Justice League and the Cyborg Superman Saga
Superman was among the several beings living on Earth to be captured by the tyrant Mongul and put into his gladiator arena on War World. Following the events that transpired there, Superman and his fellow captives (with the exception of Black Adam) formed the Justice League when they returned to Earth.

Bizarro
After trying to help the Marvel Family against their reflection counterparts from the magical mirror Phanagor, Superman unwittingly created his own by moving into the range of the mirror; however, nobody noticed the Superman that entered out of the mirror, and he flew away.

The being from the mirror finally resurfaced in Metropolis, where he went around trying to help people in various circumstances; however, he would always make matters worse when he genuinely thought he was helping (such as when to help an elderly lady cross the street he picked her up and chucked her, resulting in her death). Superman eventually received word that he was wanted for numerous crimes around the city and went to investigate. What he found was a horribly deformed, grey-skinned being dressed up in a Superman costume who was now making moves on Lois Lane. Superman tried to reason with the imposter, but ultimately ended up battling him across the city, causing much damage, until finally Lois and Superman were able to make him realize that he wasn't really Superman. Saddened by this realization, he adopted the name Bizarro. Superman took Bizarro to an isolated island, leaving him there as its protector.

Personality
Superman is very pious, boldy claiming to represnet "truth, justice, and the American way."

During his time on the Justice League, he regularly assumed a sort of unofficial leadership role. This led many members to dislike him to an extent, especially because of his actions that blatantly disregarded League consensus, which ultimately led to him being voted off of the team. Such actions could be interpreted as being based on either his arrogance or his altruism, but most likely a mix of both.

Quotations

 * 1) Superman: "Me. Me! Meee!!!"