Cooper retired from the practice of law in 1989. In June 1990, Cooper was honored with a gala screening of "Gentleman From Kentucky", a Kentucky Educational Television documentary about his life, at the John F. Kennedy Center for the Performing Arts in Washington. On February 21, 1991, Cooper died of heart failure in a retirement home in Washington. He had been preceded in death by his second wife, Lorraine, on February 3, 1985. On February 26, 1991, Kentucky's two senators, Wendell H. Ford and Mitch McConnell, gave speeches on the Senate floor praising Cooper, and the Senate adjourned in Cooper's memory. Cooper was buried in Arlington National Cemetery in Arlington, Virginia.