Captain Marvel

Billy Batson was chosen by the wizard Shazam to represent him as the superhero Captain Marvel because of his courage and pure heart.

Origin
After being chosen by the Wizard Shazam to become Captain Marvel, he was attacked by the supervillain Black Adam, who had returned to Earth after his thousands of years long exile from the planet. Captain Marvel was able to overcome Black Adam with the help of Superman, but they were not able to capture the villain.

On the Justice League
Captain Marvel's next major appearance was in the Sahara Desert, when he once again fought alongside Superman to defeat Eclipso.

Captain Marvel was invited to join the Justice League by Superman. For his trial, he had to spar with Wonder Woman, who was so impressed by his abilities and character that she would go on to train him extensively in her combative techniques.

During the attack on the Hall of Justice secretly directed by Cyborg Superman, Captain Marvel was apparently killed, leading to his sister Mary to be granted the powers of Shazam and become the superheroine Mary Marvel. She also ended up taking his place on the Justice League. However, Captain Marvel had not really been killed, but had been taken to the Rock of Eternity to get further training from Shazam. He finally reappeared on Earth to help the Justice League defeat the Golden Pharaoh, who had been resurrected by Eclipso. Captain Marvel was able to defeat Golden Pharaoh only with the help of his nemesis Black Adam, who had defeated Golden Pharaoh back in ancient times and sealed him away.

Captain Marvel was present when the Justice League battled Cyborg Superman inside the Fortress of Solitude and recessitated the comatose Superman.

After Captain Nazi badly injured Billy's friend Freddy Freeman and killed Freddy's father, Captain Marvel gave up part of his power to grant Freddy the ability to become Captain Marvel, Jr.

During the time when the Seven Deadly Sins escaped from the Rock of Eternity and were possessing members of the Justice League, Captain Marvel was stricken with the Sin of Slothfulness. Captain Marvel, Jr. was able to overcome the Seven Deadly Sins and rescue the Justice League from their embarrassing situation.

Captain Marvel was instrumental in the conflict with Tyr and Mongul, Jr., being able to defeat Mongul, Jr. and then torture him with his ultra-powerful Shazam bolt multiple times.

Earth-Two Possibility
There is a Billy Batson in the parallel world of Earth-Two. While not showing up physically, his voice was heard on his public radio broadcast for Whiz Studios, as was made evident by his signature signing off upon the closing of the show.