Born in Mississippi and raised in Kentucky, Sam Gilliam moved to Washington, D.C., in 1962, where he became a central figure of the Washington Color School. He initially worked within the movement's focus on color field painting before achieving a major breakthrough in the mid-1960s by experimenting with the physical structure of the canvas.

Gilliam is recognized for his innovative process of staining, folding, and draping unprimed canvas, which transformed traditional two-dimensional painting into immersive, sculptural environments. His work often incorporated vibrant, layered pigments and metallic paints, challenging the boundaries between painting, sculpture, and architecture.

Throughout his career, Gilliam maintained a significant presence in the American art scene, serving as an influential educator and artist in the nation's capital. His work is held in numerous major museum collections, reflecting his enduring impact on the development of abstract expressionism and contemporary installation art.