Emmett Lathrop "Doc" Brown was born in 1920 in Hill Valley, California.
Although Doc has created many inventions, he is most famous for his invention of the Flux Capacitor, which is what makes time travel possible. He came up with the idea on November 5, 1955, when he was standing on his toilet, hanging a clock, slipped, and hit his head on the edge of the sink. When he woke up, he had a vision of the Flux Capacitor.
He spent many years developing it, and the Delorean Time Machine was unveiled to the world on October 26, 1985. He and his close friend Marty McFly went on many adventures together with the machine, until Doc finally got his own lab at the Institute of Future Technology in 1991. The Institute was eventually closed down and reopened as Krusty Land. Doc was hired to help run the theme park. No one has heard from him since, although there have been some reported sightings of him, walking around Universal Studios, where Krusty Land is at.
For more information visit: http://bttf.wikia.com/wiki/Emmett_Brown.