FDR did not have a chief of staff. Some say that he acted as his own chief of staff. Unlike most other modern presidents, FDR liked to hear different points of view informally. He did not respect lines of authority and talked to people privately throughout the government without going through channels.
James H. Rowe Jr., *, FDR Presidential Assistant (Democrat), Oral History Interview, The Truman Library, September 30, 1969