The following is a list of Postmasters who have served in the Marion, Illinois Post Office.
| Name | Title | Date Appointed |
| Willis Allen | Postmaster | 01/30/1840 |
| John M. Cunningham | Postmaster | 03/18/1842 |
| Napoleon B. Calvert | Postmaster | 02/10/1843 |
| Robert T. Hopper | Postmaster | 03/10/1851 |
| Joseph Hopper | Postmaster | 11/05/1852 |
| Patrick H. Lang | Postmaster | 06/15/1861 |
| discontinued on September 13, 1861 | ||
| reestablished on October 11, 1861 | ||
| Patrick H. Lang | Postmaster | 10/11/1861 |
| Robert M. Elliott | Postmaster | 05/20/1865 |
| Napoleon B. Calvert | Postmaster | 03/13/1866 |
| Samuel Cover | Postmaster | 12/20/1866 |
| Amzi F. White | Postmaster | 02/02/1869 |
| William N. Mitchell | Postmaster | 04/01/1870 |
| Edward E. Mitchell | Postmaster | 01/08/1880 |
| James P. Copeland | Postmaster | 06/14/1880 |
| Romulous D. Holland | Postmaster | 07/20/1885 |
| Hartwell Hendrickson | Postmaster | 04/15/1889 |
| John Goodall | Postmaster | 05/05/1894 |
| Lorenzo D. Hartwell | Postmaster | 01/10/1898 |
| Henry C. Jones | Postmaster | 12/10/1900 |
| Harry Holland | Postmaster | 06/13/1913 |
| Willis T. Harris | Postmaster | 09/08/1922 |
| Frank Odum | Acting Postmaster | 11/28/1931 |
| Oldham Paisley | Postmaster | 06/01/1932 |
| William H. McAlpin | Acting Postmaster | 03/10/1934 |
| William H. McAlpin | Postmaster | 03/18/1935 |
| Don C. Moss | Acting Postmaster | 05/01/1940 |
| Don C. Moss | Postmaster | 06/25/1940 |
| Albert O. Ledbetter | Acting Postmaster | 06/30/1946 |
| Albert O. Ledbetter | Postmaster | 03/17/1949 |
| John Paul Smothers | Acting Postmaster | 06/30/1955 |
| John Paul Smothers | Postmaster | 09/06/1957 |
| James L. Eveland | Officer-In-Charge | 08/11/1976 |
| Albert H. Vanhorn | Postmaster | 01/29/1977 |
| Don Evans | Officer-In-Charge | 10/26/1987 |
| William E. Knight | Postmaster | 04/09/1988 |
| William Ross | Officer-In-Charge | 01/10/1997 |
| Elbert Simon | Postmaster | 06/07/1997 |
| Greg Rednour | Officer-In-Charge | 02/26/2004 |
| Curtis D. Shadowens | Postmaster | 10/30/2004 |
| Kathryn M. McCann | Officer-In-Charge | 12/28/2011 |
| Kathryn M. McCann | Postmaster | 06/30/2012 |
(Extracted from U.S. Postal Service historical records)