| Name | John Pfeiffer |
| Agency | Chicago Fire Department |
| Rank | Firefighter |
| Type of Firefighter | Career |
| Age Range | [Unknown] |
| Sex | Male |
| Date of Birth | 0/0/0 |
| Date of Death | 9/6/1959 |
| Cause of Death | Stress/Overexertion |
| Nature of Death | Heart attack |
| Attribute of Death | [not applicable] |
| Type of Duty | Firehouse duties |
| Incident Name | N/A |
| Incident City | Chicago |
| Incident State | IL |
| Incident Date | 9/6/1959 |
| Incident Location | Firehouse |
| Incident Attribute | [Not applicable] |
On September 6, 1959, Chicago Fire Department Firefighter John Pfeiffer died in the line of duty after suffering a heart attack in company quarters at 1403 South Michigan Avenue.
Pfeiffer became a member of the Chicago Fire Department on November 1, 1943.