Morris was born September 18, 1955 and grew up in Hermosa Beach, California. His father, Jerry, had been a budding jazz drummer in his youth and practiced with visiting jazz groups at the Lighthouse Café. Jerry later opened a bait shop in the 1970s and struck up a friendship with jazz record producer Ozzie Cadena (both men's sons, Keith and Dez, later became singers in Black Flag). Keith attended Mira Costa High School, where brothers Greg and Raymond Ginn were also students, and graduated in 1973. He then studied fine art and painting at the Pasadena Arts Center while working at his father's bait shop. One of his co-workers at the shop was Bill Stevenson, a Mira Costa student eight years Morris' junior who would also go on to be a member of Black Flag.
