He grew up in Lakeland, Florida. When he was 18, he won Florida state contests on fiddle and mandolin. He considers his discovery of David Grisman's music a significant event in his life, admiring how Grisman combined jazz and Latin styles into his own form of bluegrass. After Marshall moved to California, he collaborated with Grisman on film music and soon after was invited by Grisman to join the quintet. He was a member of the David Grisman Quintet from 1985–1990, touring with Jerry Douglas, Béla Fleck, Tony Rice, Mark O'Connor, Stéphane Grappelli, and Darol Anger.
