James Buchanan - Administration
| First Lady | Harriet Lane |
| Vice President | John C. Breckinridge (1857–1861) |
| Secretary of State | Lewis Cass (1857–1860) |
| Secretary of State | Jeremiah S. Black (1860–1861) |
| Secretary of the Interior | Jacob Thompson (1857–1861) |
| Attorney General | Jeremiah S. Black (1857–1860) |
| Attorney General | Edwin M. Stanton (1860–1861) |
| Postmaster General | Horatio King (1861) |
| Postmaster General | Aaron V. Brown (1857–1859) |
| Postmaster General | Joseph Holt (1859–1861) |
| Secretary of the Treasury | Howell Cobb (1857–1860) |
| Secretary of the Treasury | Philip F. Thomas (1860–1861) |
| Secretary of the Treasury | John A. Dix (1861) |
| Secretary of the Navy | Isaac Toucey (1857–1861) |
| Secretary of War | John B. Floyd (1857–1860) |
| Secretary of War | Joseph Holt (1861) |