Born in Jackson County, Ohio in 1858, Purley Baker was trained in the public schools of Jackson and Green counties. He was licensed to the ministry after two years of teaching in the public schools. Baker became an ordained Methodist minister moving from congregation to ever larger congregation in Ohio. He gained a reputation as an enemy of the saloon.

While at the Old Third Street Methodist Church of Columbus, Ohio, he finally succumbed to the persuasion of Howard Hyde Russell and joined the Ohio Anti-Saloon League. After a year, he became state superintendent and for five years battled for the League's interests in Ohio.

In 1903, Baker was elected to succeed Russell as superintendent of the national organization. When the League moved its printing operation to Westerville, Ohio, he moved to a home near the Otterbein campus. From Westerville, he commanded the forces of the League as they spread the dry message across the country. While he was in command, the decision was made to move toward national prohibition and the successful passage of the 18th amendment was achieved.

During the decade of the 1920's, Baker was not an active leader. He lived in semi-retirement. His death in 1924 after a lengthy illness forced a power struggle among the leadership of the League.