Rubin was raised in Bonita, California. He began playing drums at the age of eight, when he discovered his father's 1968 Silver Sparkle Ludwig drum kit set up in the garage. After three months of "toying" with the kit, he had taught himself to play and was jamming with his older brothers. By age nine, he was ready to play for F.o.N., a band that eventually would do three stints on the Vans Warped Tour, where Rubin would also fill in on drums for bands such as NOFX. In 1999, F.o.N. opened Woodstock '99 on the Emerging Artist Stage; as a result, 11-year-old Rubin gained entry into the Guinness Book of World Records as the youngest musician to ever play on a Woodstock stage.
Shortly thereafter, Rubin submitted a video to Modern Drummer Magazine of him doing a solo during an F.o.N. performance, which was picked by the magazine as the winning entry in its "Best Undiscovered Drummer Under the Age of 18" contest. The winner of the 18-and-over category came from Argentina, and both drummers were invited to perform at the 2000 Modern Drummer Festival, by which time Rubin had turned 12. He has taken lessons from Blink-182's drummer Travis Barker and The Hooters' drummer David Uosikkinen.