John Kiffmeyer, also known as Al Sobrante, left home at an early age and reportedly fell while running and got amnesia. He awoke in front of a sign saying 'Welcome to El Sobrante, California.' Sobrante misunderstood the sign and thought it read 'Welcome Al Sobrante, to California.' Thus he took on the name Al Sobrante.

Al found Tré Cool (Frank Edwin Wright III), current drummer for Green Day, playing music in Tré's garage. Tré taught Al Sobrante how to play the drums and let him sleep in his garage. Al Sobrante joined the punk rock group Sweet Children, who later changed their name to Green Day. He drummed on their first CD, "1,039 Smoothed Out Slappy" Hours, and on several of their EP's. He did one tour with them.

In 1990, when the rest of the band wanted to pursue music as a career and Sobrante didn't, he left to attend college, eventually joining up fellow Berkeley band The Ne'er Do Wells. Though, this is the official story, it is rumored that Sobrante was away on a dentist trip, and the band didn't have anyone to play with them, so they let Tre Cool play a gig, and decided that he sounded better and dropped Sobrante. Though, he left Green Day on good terms with the others and later helped with production on their second album Kerplunk!. Tré Cool took his place, and by the end of 1994, Green Day had achieved massive mainstream success.

Credits:

Thanks to Greek Stink Breath for the biography.