Born in Cardiff, Wales in 1950, Marsh emigrated with his family to Auckland, New Zealand, where he was educated at Westlake Boys' High School. He then attended the Elam School of Fine Arts at the University of Auckland from 1967 to 1970, where he obtained a Diploma of Fine Arts. From 1975 to 1978 he studied at the Royal College of Art in London, gaining a MA in painting.
