William O. Butler graduated from Transylvania University and studied law, gaining admission to the bar. He served in the War of 1812, participating in significant battles and earning distinction. Butler practiced law and held various political offices, including serving in the Kentucky House of Representatives and as a congressman. During the Mexican–American War, he commanded a division and was later appointed commanding general in Mexico City. Despite being nominated for vice president in 1848, he lost the election. Butler remained politically active, opposing the extension of slavery and advocating for the Union during the Civil War.

William O. Butler's political identity is marked by a unique blend of military valor and ideological moderation. Despite his military exploits, he consistently advocated for gradual legal emancipation and opposed the extension of slavery, revealing a calculated approach to social issues. His attendance at the peace conference of 1861 underscores his commitment to preserving the Union, even as he navigated the fraught waters of sectional tensions. Butler's rhetorical style likely balanced a respect for tradition with a pragmatic willingness to adapt, making him a fascinating figure in the context of 19th-century American politics.