Eastman, who was born in Waterville, New York, began his career in banking and insurance but turned from this to photography. In 1880 he perfected the dry-plate photographic film and began manufacturing this. He produced a transparent roll film in 1884 and in the same year founded the Eastman Dry Plate and Film Company. In 1888 he introduced the simple hand-held box camera that made popular photography possible. The Kodak camera with a roll of transparent film was cheap enough for all pockets and could be used by a child. It was followed by the Brownie camera, which cost just one dollar.

Eastman gave away a considerable part of his fortune to educational institutions, including the Massachusetts Institute of Technology. He committed suicide in 1932.