John A. Cockerill, the paper's managing editor, killed Alonzo W. Slayback with a pistol shot on the 13th of October 1882. Cockerill claimed self-defense after Slayback barged into his office to demand an apology for articles questioning James Overton Broadhead's political integrity.
Joseph Pulitzer wrote a document on the 10th of April 1907 that declared the St. Louis Post-Dispatch would never belong to any party and always fight demagogues of all parties. This platform established a radical stance that the publication would never tolerate injustice or corruption and always oppose privileged classes and public plunderers.
The St. Louis Post-Dispatch introduced the Weatherbird cartoon on the 11th of February 1901. Harry B. Martin created the whimsical bird to accompany the daily weather forecast, and Amadee Wohlschlaeger was the first artist to draw it in color.
The St. Louis Post-Dispatch published the secret protocols for the 1939 Molotov, Ribbentrop Pact on the 22nd of May 1946. This agreement between Nazi Germany and the Soviet Union divided Eastern Europe, and the paper became the first newspaper in the world to publish these secret protocols.
The St. Louis Post-Dispatch led a Pulitzer Prize-winning campaign to clean up the city's air during the late 1930s and early 1940s. The paper's investigative reporting exposed severe pollution problems and mobilized public opinion to demand action, resulting in significant improvements to the city's air quality.
The St. Louis Post-Dispatch announced the closure of its St. Louis press facility in September 2024. The paper decided to outsource printing to a facility in Columbia, Missouri, which resulted in the loss of 72 jobs and a move to a six-day printing schedule.