William Slade graduated from Middlebury College and was admitted to the bar in 1810, subsequently practicing law in Middlebury. He held various roles, including serving as Vermont Secretary of State and Judge of the Addison County Court. Slade transitioned to the public sector, working in the U.S. State Department and representing his state in the U.S. House of Representatives. He later served as Governor of Vermont and contributed to educational reforms, including advocating for female teachers in the western United States.

William Slade's political career is marked by a blend of progressive educational reforms and unexpected advocacy on slavery, revealing an ideologically agile approach. His efforts to integrate female teachers in western schools and advocate for public school reorganization showcase a forward-thinking stance on education. Slade's challenge to the gag rule on slavery in 1837, despite leading to a stricter rule, indicates a calculated strategy to address contentious issues. This juxtaposition of progressive education policies with bold anti-slavery actions highlights a nuanced and strategic political identity.