Much of this information is gleaned from Dave's Warped Space's DC Comics site and the Superman Through The Ages' Silver Age Superman page. The Silver Age Superman had no solid birth year, as his birth remained basically a constant 30 years before whatever story you read.
Real Name: Clark Kent / Kal-El
Birth year undefined
First appearance circa Action Comics #221, but not clearly defined
Fictional history:
Kal-El was born on Krypton, and lived there for three years, learning about his family, his heritage, Krypton in general, and his native language. His father, Jor-El, had discovered the impending doom of Krypton, but failed to convince the apparently ignorant High Council of the need to evacuate the planet. Jor-El, therefore, build a small starship with wormhole technology which he placed his son in and launched towards Earth just before Krypton exploded. Prior to this, Jor-El had experimented with such rockets. The final trial run involved placing the family puppy, Krypto, into a rocket and launching it. Though it should have returned to Krypton, it was struck by a meteor and redirected towards Earth. Also, a whole city (Argo City) exploded into space intact, inhabited in part by Jor-El's brother, Zor-El, and his daughter Kara, who would later be launched to Earth. Actually, I think just about everyone found a way off Krypton to appear at one point or another during the career of the Silver Age Superman. Regardless, Kal-El's rocket went through a wormhole which also pulled chunks of the destroyed Krypton along with it, making for a rather quick trip to Earth.
When Kal-El crash-landed near Smallville, he was found by John (or Jonathan) and Martha Kent, both older than 50 at the time. They took the child to an orphanage, and quickly adopted him. He was named Clark, and they quickly discovered he was no normal child. This version of Superman was extremely powerful as soon as he arrived on Earth. Due to the yellow sun (first introduced in 1960, but not resembling the solar battery concept of today, his invulnerability being likened to a super sun tan) and the lesser gravity, this toddler was stronger than ten men, invulnerable, and could fly. While still young, he learned to see through walls, emit heat vision, use super-breath to freeze whole lakes, exceed the speed of light, and even travel through time. Around the age of ten, Clark decided to begin his career as a super-hero. Using indestructible Kryptonian materials from the space ship, Martha made a uniform for Clark to wear. Please don't ask how a 60 year old woman was able to sew indestructible material. Maybe she used a kryptonite needle, or maybe Clark's mom is actually more powerful than he is, I just don't know. With his uniform, Clark began his dual persona of the super-hero Superboy and the awkward, wussy, glasses wearing nerd Clark Kent. Along with his dog, Krypto, many adventures ensued as Lana Lang (the Smallville replacement for Lois Lane) tries constantly tried to prove that Superboy and Clark were one and the same, and Pete Ross (Smallville's replacement for Jimmy Olsen) acted as Clark's best friend.
Eventually, Ma and Pa both passed on. This prompted Clark to move to Metropolis, get a job at the Daily Planet with a Superman scoop, and meet his new Lana Lang, Lois Lane. As Superman protected Metropolis, his powers continued to increase until he could do anything. Also, more and more objects from Krypton showed up, since the whole frickin' planet apparently found its way through Kal-El's wormhole to show up on Earth. The most dangerous and colorful of these objects was kryptonite. Red, green, gold, blue, and rainbow. Green was the most common form, which caused weakness, pain, and eventual death to Superman. After a while, it seems like every two-bit thug in Metropolis was given a chunk of kryptonite at his bar mitzvah.
It was at this point, around 1970, that DC decided to streamline the DC Universe and get rid of more "ridiculous" concepts, now known as "The Sandman Saga." One big change was Kryptonite. A nuclear experiment gone awry converts all kryptonite on Earth to lead, removing this plot device from the writers hands (though there would still be kryptonite in space, the writers later discovered). Not done with this restructuring, Clark Kent is reassigned to work as a roving reporter for WGBS, a television station. Also, Clark loses the wussiness that he'd had to this point. Heck, he's an impressive enough persona to get an on-air gig as a TV reporter, so he couldn't have been meek and timid. Over the few months, Superman goes through a story arc involving the leeching of his powers. He eventually emerges with his powers trimmed down by about one third, and the character more connected to his human upbringing. Of course, one issue later he's back to surviving a supernova explosion.
The next, and final, main chapter in the Silver Age Superman's life was the Crisis. His cousin, Supergirl, died in the Crisis. Though Superman was ready to sacrifice himself, the Earth-2 Superman would not allow it, sending this Superman back to Earth while he stayed and killed the Anti-Monitor.
It took about a year, following the end of the Crisis, before DC continuity was really revamped, so there continued to be a year of stories about this version of Superman before John Byrne gave us the post-Crisis version. One of these stories was "Whatever Happened to the Man of Tomorrow?" and shows us the future of Superman after marrying Lois Lane. Even today, stories are still written about the Silver Age Superman, though. Frank Miller's "Batman: The Dark Knight" and it's sequel DK2 both seem to follow pre-Crisis history, showing Superman as a reluctant pawn of the anti-superhero government, and facing down Batman as the future of our favorite heroes is left in question.
