E. Paul du Pont was married in 1910 to Jean Kane Foulke du Pont, the granddaughter of William Foulke, discoverer of the first full dinosaur skeleton in the United States (Hadrosaurus foulkii), in Haddonfield, New Jersey, in 1858.
He purchased and took over management of Indian in 1930, where he led a purge of corruption in the prior management. According to the Motorcycle Hall of Fame in Ohio, du Pont saved Indian from financial ruin.
He was an avid hobbyist of waterwheels and millwork, and is said to have insisted upon always performing maintenance personally on the ornamental waterwheel in the gardens of the du Pont family estate.
After E. Paul du Pont's death, his wife founded the E. Paul du Pont Endowment for the Study of Crime, Delinquency, and Corrections at the University of Delaware, which led to the creation of their criminal justice programme.