Marshall was born at St Just in Penwith, and is a painter working from Trevelloe Farm, Lamorna within the studio complex of artists and craftsmen who work there. 

He is part of what is known as the Lamorna Valley Group. In the summer of 2011, his work was shown at the Academy Gallery, Bath, Ontario, curated by Simon ANDREW. The others included in the exhibition, 'Painters 4 - UK to CA', were Kevin EDWARDS, Tamara MAZURENKO and Jim WOOLLEY.