Ernest Lawrence Thayer was born on August 14, 1863, in Lawrence, Massachusetts. He graduated with a BA in philosophy from Harvard University in 1885, where he was a member of the Hasty Pudding Club and edited the Harvard Lampoon.
At Harvard, Thayer met William Randolph Hearst, who would later run the San Francisco Examiner and hire Thayer to write a humorous column for the newspaper. On June 3, 1883, Thayer published what would become his most famous work, the poem "Casey at the Bat," under the pen name Phin. The poem gained popularity after the performer William DeWolf Hopper incorporated a recitation of it into his theatrical and radio performances.
Thayer moved to Santa Barbara, California, in 1912. He died in Santa Barbara on August 21, 1940.