[7] While still in high school, Marshall purchased his first camera and began documenting musicians and artists in San Francisco.

[8][9] He photographed Jimi Hendrix setting his guitar on fire at the Monterey Pop Festival, and Johnny Cash at San Quentin.

His pictures of Neil Young, Janis Joplin, Bob Dylan, Jim Morrison, the Allman Brothers, The Who, Led Zeppelin, the Grateful Dead, the Jefferson Airplane, Guns N' Roses, Santana and the Beatles "helped define their subjects as well as rock 'n' roll photography itself.

"[1] His work was included in the Annie Leibovitz edited book, Shooting Stars: the Rolling Stones Book of Portraits (Straight Arrow Press, 1973), alongside photographers Herb Greene, Baron Wolman, Annie Leibovitz, Nevis Cameron, Ed Caraeff, David Gahr, Bob Seidemann, Barry Feinstein, Ethan Russell, and others.

Marshall lived in San Francisco, but he died in New York City while on a trip during which he was scheduled to speak in SoHo.