He first appeared in the comic book, Batman: Vengence of Bane #1.
A mercenary for hire, Bane gets his power from a drug called "Venom," which is pumped directly into his brain, which increased his muscle mass and increased his strength.
His father was a revolutionist that was against the Santa Prisca government who escaped imprisonment. The government decided to imprison Bane in his father's place. To pass his undeserved life sentence, Bane spent his time reading all the books the prison library had to offers and did some bodybuilding. This impressed a scientist who used him to experiment with Venom, that killed others.
When he was hired to kill Batman, Bane broke the inmates out of Gotham to tire Batman out. When he encountered the Dark Knight, he was able to defeat him and broke Batman's spine, becoming one of the few people to defeat the Dark Knight. Batman spent his time recovering and eventually was able to defeat Bane by removing the tubes that supplied him with Venom.
Despite the power Venom gives him, Bane is also addicted to it and needs to have it every 12 hours or he will suffer from side-effects.
Bane was one of the few people to determine Batman's real identity.