Deem traveled the United States speaking and exhibiting his art, but lived most of his life at 10 West 18th Street in New York's Flatiron District.

Among the artists whose work he reproduced were Caravaggio, Jean-Baptiste-Siméon Chardin, Jean Auguste Dominique Ingres, Winslow Homer, Andrea Mantegna, Henri Matisse, Pablo Picasso and, especially, Johannes Vermeer, about whose style he wrote a book.

During a 1993 visit to New York, Deem noted to his great-nephew, Kenneth J. Knight, Ph.D., that his favorite artist was Johannes Vermeer.

"The artist George Deem (1932-2008) had a unique relationship to and vision of the masterpieces of the past, especially the landmarks of Western painting that date from the Renaissance to the modern era.

As Deem himself acknowledged, his abiding interest was in the two quintessential characteristics of Western art: first, the use of oil paint as a medium; and second, the development of a convincing system of perspective.