He pioneered and mastered the use of leather as a sculptural material, using it to create musical instruments, theatrical costumes, wall hangings and free-standing works. Greenwood studied Art and Design at Reigate School of Art in Surrey, England. He immigrated to Australia in 1962, establishing himself as a graphic designer.
In 1972 he moved to Deloraine, Tasmania where he converted Bowerbank Mill into a craft gallery and studio. He later established his home and studio on Mount Barrow, near Launceston. Between 1985 and 1989 he was the head of the Leather hop at the Canberra School of Art.
He had 26 solo exhibitions, in Australia and internationally. His contribution to the arts was recognised in the Australia Day honours of 2005, shortly before his death.