Born circa 1935 in the Adirondack Mountains of New York, Marsh originally resided in rural Connecticut. His painting career was launched at the age of twelve, after which he received awards and scholarships for his efforts. His formal art training took place at the Art Center College of Design in Los Angeles.
Marsh participated in the field of industrial design in Detroit with General Motors, establishing a successful industrial design firm in San Francisco several years later.
In 1972 John Marsh and his wife left San Francisco to build their home/ studio in the foothills of California's Sierra Nevada Mountains.
John Marsh is a member of the National Watercolor Society.
Marsh's work was sold in Sedona, Arizona during the 1980's at the El Prado Galleries.