In college, Thayer was a member of the Harvard Lampoon staff. When the Lampoon’s business manager, William Randolph Hearst, went to California to run the newspaper his father gave him, Thayer and two other Lampoon writers went with him.
On June 3, 1888, Thayer published Casey at the Bat under the nom de plume Phin in the San Francisco Examiner. It was his last column. He would return to Worcester to help run his family’s mills, later moving to Santa Barbara, Calif., where he wrote scholarly articles about philosophy.
Hopper was an ardent New York Giants fan, and a friend of his clipped the poem from the New York Sun and gave it to him.
Hopper first recited Casey at Walleck’s Theatre in New York City on Aug. 14, 1888 – Thayer’s birthday and the day his friend Tim Keefe ended his record 19-game winning streak. Members of the New York Giants were in the audience.
(Keefe, by the way, was a Hall of Fame pitcher and another New Englander. He was born in Cambridge, Mass.)
Hopper went on to perform Casey at the Bat for nearly five decades – between acts, at curtain calls, on the radio. He recited it on a phonograph record in 1906 and in a short film in 1923.
Thayer was annoyed by controversies surrounding the poem: who wrote it, what town was represented by Mudville and who was Casey.
During my brief connection with the Examiner, I put out large quantities of nonsense, both prose and verse, sounding the whole newspaper gamut from advertisements to editorials. In general quality 'Casey' (at least in my judgment) is neither better nor worse than much of the other stuff. Its persistent vogue is simply unaccountable, and it would be hard to say, all things considered, if it has given me more pleasure than annoyance.
You can read the poem here.