Knox died of a heart attack at 70, just a few months before his widow, Annie, accepted on his behalf the Legion's first posthumous Distinguished Service Medal. Had he lived one more year, the Navy secretary would have seen the nation claim victory in World War II.
John L. Sullivan, assistant secretary of the Treasury and a past department commander of the New Hampshire Legion, said of his close friend: "He served his country in three wars ... He died as he had lived, giving the last measure of his very being to the service of his country."