Superman #53 (Jul-Aug 1948)
Superman #53's "The Origin of Superman" is the first post-War Superman origin in comics form, and the first since 1939's Superman #1. On the title splash, Superman holds his head in hands, fingers laced through his hair, looking mournful as an image of his rocket leaving an exploding Krypton, superimposed with Jor-L and Lara, floats towards the top of the page. But it's misleading: Superman doesn't acknowledge his Kryptonian roots in this story as he apparently has yet to learn them. While the radio show provided this knowledge to Clark Kent, the comics wouldn't come around to it until 1949’s “Superman Returns to Krypton.”
This time, Krypton is still an advanced planet: a Kryptonian couple lament their son Junior's inability to perform calculus in third grade, while still shy of his fifth birthday. They're more mental than physical giants this time around, and they're faced with ever-growing earthquakes. In the Council of Five meeting, Jor-El proclaims "KRYPTON IS DOOMED!" Hot on the heels of Fatman and Little Boy, Krypton's issues are now the result of an instability of the uranium core. The quakes are about to destroy Krypton like its "in one gigantic atomic bomb!" Jor-El's even equipped with a rocket model to illustrate his plan to move Krypton's populace to Earth, but the Council laugh him off for suggesting such a backwards planet.
There is no time for long nights of overwork, with Jor-El (now as in "El" and not just "L") feverish and fatigued; the "big one" starts to strike as Jor-El runs home to his wife and son. Lara refuses to get in the rocket with baby Kal-El, with the earlier "My place here is with you!" And off he goes to Earth, as the final quake topples the entire city.
The rocket lands in front of an old Model T, driven by Pa Kent. They're drawn to look middle-aged to elderly, in an outdated fashion, and hardly look like farmers. The rocket explodes right after saving the baby, who they take into an orphanage with hopes of adopting him. Baby Kal-El freaks the doctors and staff out so much with his super strength and rush the papers through so the Kents can adopt him.
Growing up on a farm, Clark's powers emerge in his teen years: A runaway tractor doesn't hurt him, he runs faster than a train, and inadvertently leaps over the house while trying to hop a fence. His X-Ray Vision emerges when he helps Ma find her glasses.
By the time Pa Kent is on his deathbed, after his mother's death, he urges him to use his amazing powers to "become a powerful force for good!"
"There are evil men in this world...Criminals and outlaws who prey on decent folk! You must fight them...in cooperation with the law! To fight those criminals best, you must hide your true identity! They must never know Clark Kent is a...A Super-Man! Remember, because that's what you are...A SUPERMAN!"
Clark looks over their graves and it reveals their names: John and Mary. He finds a reporter job to keep in touch with people, and disguises himself with glasses. Thus is born Superman!
This is the last Superman origin with him not donning the costume. until adulthood. The next time his origin is told, it is in the shadow of the Mort Weisinger era's expansion of the mythos, with retroactive points included to "foreshadow" stories from his career as Superman. With the Weisinger era giving us his early, early career to include Superbaby and then Superboy, and the supermemory of Krypton, it established Superman as a learned behavior in Clark's life, not as much a coming of age.