Beck is the son of '60s underground film actress Bibbe Hansen, who worked with Andy Warhol on a number of projects including his film Prison. Beck's grandfather Al Hansen was a member of the Fluxus art movement, which also included Yoko Ono. (thanks, Ekristheh - Halath)
His birth name is Beck David Campbell, but his father, David Campbell, left the family when Beck was young, and he took his mother's last name, Hansen.
When he signed with Geffen Records in 1994, his contract allowed to record for other labels as well. He was able to get this clause because his song Loser was a hit, which put him in a position to make demands.
Born in Los Angeles, Beck moved to New York when he was 17 and joined the Folk scene. He returned to Los Angeles when he ran out of money and began playing area coffeehouses, which is where he made a name for himself.
He is a regular musical guest on Saturday Night Live. By 2007, he had been on 6 times.
Beck's father is a Scientologist, but Beck rarely talks about his association with Scientology.