Born Michael Balzary, he is the bassist of the Red Hot Chili Peppers and widely considered to be one of the greatest rock bassists of all-time.
He met Anthony Kiedis, the future Red Hot Chili Peppers frontman, at Fairfax High School in Los Angeles. He first played jazz trumpet but was taught the bass by Hillel Slovak, who would become the Red Hot Chili Peppers' first guitarist.
He was married to Loesha Zeviar from 1988 to 1990. He got engaged to model Frankie Rayder in 2005, but the two separated before tying the knot. He and Rayder had a daughter together named Sunny. In 2019, he married Melody Ehsani.
In 2009, he and Radiohead frontman Thom Yorke formed the supergroup Atoms for Peace. They released their first album, Amok, in 2013.