The newspaper claims to be the oldest daily newspaper in Missouri, having printed daily since 1853 and tracing its lineage back to several weekly newspapers in and around Hannibal: the Commercial Advertiser, later called the Pacific Monitor, Hannibal Journal and Hannibal Journal and Western Union ; the Hannibal Gazette ; the Hannibal Messenger ; and a Palmyra weekly, the Missouri Courier, founded in 1832 and consolidated with the Gazette in 1848. The Journalconverted to a daily March 16, 1853, the Messenger in 1858. The Messenger combined with the Courier in 1863, adopting the name North Missouri Courier. The daily Courier in 1891 merged with the Daily Post, marking the debut of the name Hannibal Courier-Post. The Morning Journal was acquired in 1918. Individual owners had published the Courier-Post and its predecessors since the 1850s, including Thomas B. Morse, who had founded the Daily Post in 1886 and remained publisher of the merged newspaper until 1907. Morse sold the paper that year to Lee Enterprises, which invested heavily in its new acquisition, with a new printing press, Associated Press wire, and a new building. Lee sold the paper to Stauffer Communications in 1969. Morris Communications acquired Stauffer in 1995. GateHouse Media, purchased the Courier-Post in 2007. Quincy Media, owners of the Quincy Herald-Whig, announced their purchase of the Courier-Post in 2019.
As the hometown daily newspapers of Mark Twain, the predecessors of the Hannibal Courier-Post were an important part of the future literary star's youth. It was an advertisement in the Commercial Advertiser weekly, from February 27, 1839, that lured Twain's father John Marshall Clemens to Hannibal. Twain himself worked on the Missouri Courier, as a "printer's devil" in 1849, as he recalled in a 1908 letter to the Courier editors: Twain's older brother, Orion Clemens, briefly owned the Hannibal Journal and Western Union, 1850-1853, employing Twain as a typesetter and contributor of articles and humorous sketches. In the Autobiography of Mark Twain, Volume 1, entry 29 March 1906, Twain described his life as a printer's apprentice at the office of the "Hannibal Courier" and how a fellow apprentice was rebuked for abbreviating "Jesus Christ" to "J.C." when typesetting a sermon by Reverend Alexander Campbell. "He said, 'So long as you live, don’t you ever diminish the Savior’s name again. Put it all in.' He repeated this admonition a couple of times to emphasize it, then he went away." As Twain described it: Since the incident is described as having happened about 1847, it shows just how old some idioms of swearing are.
