Captain Steven "Steve" Grant Rogers, born in New York, on July 4, 1918 and is the only living, successful test subject of the Super Soldier Serum developed by Abraham Erskine during the Second World War.The serum enhanced his body, promoting exceptional physical capabilities. The patriotic super soldier was given the title of Captain America and fought against the Nazis and their associated terror group HYDRA. Rogers was frozen for nearly seventy years and awoke in the twenty-first century, where he joined the Avengers as their team leader. After the Battle of New York, Rogers became a S.H.I.E.L.D. agent. He went on many covert missions with agent Natasha Romanoff and S.H.I.E.L.D. counter-terrorism team, Strike. Both Rogers and Romanoff discover that HYDRA has secretly operated within S.H.I.E.L.D. for decades. Rogers, with the help of Sam Wilson was able to destroy HYDRA's Insight Helicarriers for Project Insight.

Captain America represented the pinnacle of human physical perfection. He experienced a time when he was augmented to superhuman levels, but generally performed just below superhuman levels for most of his career. Captain America had a very high intelligence as well as agility, strength, speed, endurance, and reaction time superior to any Olympic athlete who ever competed. The Super-Soldier formula that he had metabolized had enhanced all of his bodily functions to the peak of human efficiency. Most notably, his body eliminates the excessive build-up of fatigue-producing poisons in his muscles, granting him phenomenal endurance.Captain America had mastered the martial arts of American-style boxing and judo, and had combined these disciplines with his own unique hand-to-hand style of combat. He had also shown skill and knowledge of a number of other martial arts. He engaged in a daily regimen of rigorous exercise (including aerobics, weight lifting, gymnastics, and simulated combat) to keep himself in peak condition.

Steve Rogers was a scrawny fine arts student growing up during the Great Depression. His alcoholic father died when Steve was a child, and his mother passed away from pneumonia after he graduated high school. In early 1940, appalled at Nazi Germany's horrific atrocities, Steve attempted to enlist in the army. Failing to pass physical requirements, he was invited to volunteer for Operation: Rebirth, a project intended to enhance US soldiers to the height of physical perfection via the inventions and discoveries of Professor Abraham Erskine. Rogers eagerly accepted and became the first test subject. After injections and ingestion of the "Super Soldier Serum," Rogers was exposed to a controlled burst of "Vita-Rays" that activated and stabilized the chemicals in his system. The process successfully altered his physiology from its frail state to the maximum of human efficiency, including greatly enhanced musculature and reflexes. Soon after, Professor Erskine was assassinated by a Nazi operative, leaving Steve the sole beneficiary of Erskine's genius.