Steve Rogers grew up in Brooklyn in the 1940's, a scrawny kid. He attempted to enlist in the army around the time the United States entered World War II only to be turned away due to his poor constitution. A U.S. officer offered Rogers an alternative way to serve his country by being a test subject in project, Operation: Rebirth, a top secret defence research project designed to create physically superior soldiers. Steve voluntarily underwent six months of injections of the formula dubbed the "Super Soldier Serum", surgery, and other experimental treatments supervised by Dr. Abraham Erskine, becoming the world’s first genetically-enhanced super-soldier.
After the assassination of Dr. Erskine, the authorities seemed unable to replicate the process. Roger was re-imagined as a superhero who served both as a counter-intelligence agent and a propaganda symbol to counter Nazi Germany's head of terrorist operations, the Red Skull. Clad in stars-and-strips military fatigues, he became “Captain America“, his image used to bolster Allied recruiting. Rogers made friends with James Buchanan "Bucky" Barnes, at Camp Lehigh in Virginia. Barnes lost his father (a soldier during WWII), and was adopted by Camp Lehigh. Barnes underwent rigorous training and was assigned to be Captain America's sidekick
Throughout World War II Captain America undertook numerous covert operations, often accompanied by Bucky. In the closing days of World War II in 1945, he led an assault on a base where the Nazis were launching a prototype nuclear bomb at the White House. As the rocket launched, Rogers and Barnes climbed aboard and wrecked its guidance system, causing it to explode seconds later. Steve was thrown clear into the icy Arctic Ocean. Neither his body or Bucky's were found, and both were presumed dead.
Rather than dying, Rogers seemingly fell into suspended animation and was found decades later by a team of marine biologists.