William Henry Seward was an American politician who served as United States Secretary of State from 1861 to 1869, and earlier served as governor of New York and as a United States senator. A determined opponent of the spread of slavery in the years leading up to the American Civil War, he was a prominent figure in the Republican Party in its formative years, and was praised for his work on behalf of the Union as Secretary of State during the Civil War. He also negotiated the treaty for the United States to purchase the Alaska Territory.

The United States secretary of state (SecState) is a member of the executive branch of the federal government and the head of the Department of State. The office holder is the second-highest-ranking member of the president's Cabinet, after the vice president, and ranks fourth in the presidential line of succession; first amongst cabinet secretaries.