Born in London in 1933, Leon came to the United States in 1951 to study at Temple University's Tyler School of Art. He was an art critic for the Philadelphia Inquirer from 1959–1962 and taught at the Philadelphia College of Art (now the University of the Arts) from 1959–1970. He moved to the California Bay Area in 1972 and taught at California College of Arts and Crafts (now California College of the Arts) until 1993. Throughout his career, Leon looked intently at Surrealist sculpture, particularly that of Alberto Giacometti. Though primarily a sculptor, favoring wood and bronze, Leon worked in a variety of media, including collage, drawing, and site-specific installation. Toward the end of his life he became interested in natural forms, especially landscape.