Born and raised in the Watts neighborhood of Los Angeles to Japanese parents, George and Alice Sumida, Gregory Sumida is a painter of "Old World dedication". He grinds his own paints, stretches the canvases and makes the frames. His primary subjects are Plains Indians in landscape, such as Crows and Shoshones, and his primary media are gouache, charcoal, watercolor, tempera, and oils. His styles vary from impressionism to realism to western to Japanese influence, and he is dedicated to continually changing and growing.

Sumida is self taught and began selling paintings at age 15. His life-changing inspiration came from a high school trip to the Los Angeles Art Museum and from a conversation about Andrew Wyeth with actor Charlton Heston. Sumida expressed great admiration for Wyeth, and Heston suggested he write to him. Amazed at getting a response, Sumida not only received a cordial note but a critique of a painting he had sent. Wyeth also advised him: "Don't take lessons."

He is also a photographer, writer, musician and philosopher.

Sources include:
Stephen Rebello, "The Last Alchemist", Southwest Art, March 2006, pp. 134-139
Peggy and Harold Samuels, Contemporary Western Artists