John Lewis enrolled at the University of California–Berkeley as a graduate student of architecture, where he was introduced to glassblowing by Marvin Lipofsky, the founder of the school's glass program. Lewis opened his hot-glass studio in Oakland in 1969, one of the first in the Bay Area. About ten years later, he received a grant from the National Endowment for the Arts that led him to explore cast glass as a sculptural medium. He designed a furnace especially for casting glass and began experimenting, pouring liquid glass into forms of various sizes and shapes. Today, he creates cast-glass furniture pieces and decorative vessels. Lewis has collaborated with numerous artists and architects to create site-specific projects and memorials, most notably the Oklahoma City National Memorial, which commemorates the 1995 bombing of the Alfred P. Murrah Federal Building.