Charles E. Duffin was born August 26, 1880 in Georgetown, Indiana. He attended the Kentucky School of Medicine from 1900 to 1902, graduating that spring. He married Cora E. Sprinkle (1877-1956) in 1902 and had two children, Charles Edward Duffin, Jr (who died of typhoid at age 12), and Roma Elizabeth Duffin.
Dr Duffin practiced medicine in Louisville and in Richmond, Indiana until 1932 when he joined the US Public Health Service. He practiced medicine with native Americans in Oklahoma, and was stationed in Florida, Georgia, the Evansville U S Marine Hospital, and served as examining physician to recent immigrants at Ellis Island. He resigned from the USPHS in 1937, and returned to Indiana. Dr Duffin died in Richmond, Indiana on November 21, 1940.