Marshall is a member of the Conservatory faculty and teaches mandolin. He attended Occidental College, graduating in 1980 Cum Laude, Phi Beta Kappa, and with Honors in Music.
Marshall is an active performer. In addition to solo performances throughout the country, he has been a Featured Guest Artist with a number of distinguished orchestras, including the Houston Symphony, Phoenix Symphony, Buffalo Philharmonic, Long Beach Symphony, Grand Rapids Symphony, Fort Worth Symphony, San Antonio Symphony, Jacksonville Symphony, and Pensacola Symphony. He has also released several recordings.
Marshall has given Master Classes at several international mandolin conferences, including Classical Mandolin Society of America, Mandolin Symposium, and the American Mandolin and Guitar Summer School. His first method book, "Duo-Style A to Z," describing advanced solo mandolin performance techniques in detail, was published in 2004.