A native of Los Angeles, California, Krieger learned to play guitar when he attended Menlo School (formerly a boarding school in the San Francisco Bay area). He started by tuning a ukulele like the bottom four strings of a guitar and imitating a flamenco guitar record. He later purchased a flamenco guitar on a Christmas vacation in Puerto Vallarta in 1963 and mastered the style without benefit of lessons. He gradually grew tired of playing flamenco and helped form a jug band called the Back Bay Chamberpot Terriers with Bill Wolff (later of the Peanut Butter Conspiracy). He formed The Doors with keyboard player Ray Manzarek, drummer John Densmore and vocalist Jim Morrison. At an early Doors rehearsal Morrison heard Krieger playing bottleneck guitar and initially wanted the technique featured on every song on the first album. Krieger's fingerstyle approach to the electric guitar, eclectic musical tastes, and occasional songwriting helped establish The Doors as a successful rock band in the 1960s.
