Out of all Young's musical collaborators (aside from the late pedal steel guitarist Ben Keith), Sampedro has perhaps proven the most adept at working with the mercurial artist.

[1] Born to an émigré Spanish fishing family in a mining camp in Welch, West Virginia and raised in Detroit, Michigan, Sampedro started playing guitar at age 11.

More like a gang than a band," recalled Sampedro)[3] until he left home with his sister at sixteen "following repeated brushes with the law.

"[5] Throughout the late 1960s and early 1970s, Sampedro operated a head shop in the San Fernando Valley and "wandered between California and Mexico, dabbling in a variety of endeavors of dubious legality that gave him great insight into the human condition.

He was introduced to the band by bassist/vocalist Billy Talbot in November 1974 during aborted sessions at Chess Studios in Chicago, exactly two years after the death of original Crazy Horse second guitarist Danny Whitten.

Shortly thereafter, Talbot accompanied Sampedro to Ensenada, Baja California, where the latter was temporarily relocating due to a legal matter.

"[8] With the addition of Sampedro on rhythm guitar, Crazy Horse developed a new, streamlined hard rock sound (as opposed to the interwoven, free-form approach of the Whitten era) that served as a seminal influence in the development of grunge and noise rock while also enabling Young to focus more on his lead playing.

[11] On a 1976 tour of Europe and Japan, Sampedro and Talbot took LSD before stepping onstage at the Budokan in Tokyo.

Although he was not included in The Restless (a short-lived hard rock power trio that evolved from Ten Men Workin'), Sampedro contributed heavily to Young's 1989 album, Freedom.

Sampedro also received a belated co-writing credit on the Young anthem "Rockin' in the Free World."

"[15] On the September 30, 1989 broadcast of Saturday Night Live, Sampedro led an ad hoc ensemble (including drummer Steve Jordan and bassist Charley Drayton) that backed Young for "No More" and "Rockin' in the Free World", regarded by critics as one of the greatest live rock television performances of all time.

Sampedro's proficiency in emergent computer technology (honed during Young's experiments with the medium in the early 1980s) allowed him to cultivate another career.