U.S. Senator, U.S. Congressman. He served in the United States Congress from 1789 to 1796 representing Massachusetts, before being elected as United States Senator, serving from 1796 to 1799. In 1799 he was re-elected to the United States House of Representatives and according to the National Archives, was elected the 6th Speaker of the House, serving until March of 1801. Sedgwick was a politician and a leading lawyer in Western Massachusetts. He had always been loyal to the British Crown until the American Revolution. During the Revolutionary War in 1776, he served at the rank of Lieutenant Colonel as an aide in General John Thomas's ill-fated Canadian expedition, which was greatly outnumbered against the British, leading to a retreat. He was later engaged in procuring supplies for the patriot forces. As a Federalist, he began his political career as a member of the State house of representatives in 1780 and from 1782 to 1783. He was a member of the State senate from 1784 to 1785. He was elected to serve in the Continental Congress from 1785 to 1786 and adopting the Federal Constitution in 1788 before serving in the United States Congress the next year. After his final term in Congress, he was judge of the supreme court of Massachusetts from 1802 until his death. He became a charter member of the American Academy of Arts and Sciences in 1780. He studied law and religion at Yale University but did not graduate. He finished his law studies under a local attorney and was admitted to the bar in 1766 before beginning to practice. He gained recognition after winning the case Brom and Bett vs. Ashley in 1781. Using the quote from the Declaration of Independence, "all men are born free and equal," he and Tapping Reeve defended a female and a male slave, who had escaped from their master Colonel Ashley and were legally seeking freedom from bondage. They were made free. The ruling was upheld in an appeal in the State Supreme Court. The female slave took the name of Elizabeth "Mumbet" Freeman, and began to work as a faithful servant for him for the rest of her life and was buried in his family's plot. One of his daughters painted a miniature portrait of "Mumbet." This court ruling may have made him more famous than his political accomplishments. The home where Sedgwick resided when "Mumbet" walked the four miles from Ashley Falls still exists today, but is not open to the public. In 1777, there is a document that shows Sedgwick purchasing one slave. His oil-on-canvas portrait originally by Gilbert Stuart is on display at the National Gallery at the Smithsonian Institution. He married three times: in 1768 to Eliza Mason, who died childless in 1771; in 1774 to Pamela Dwight, whose 10 children included the author Catharine Maria Sedgwick; and in 1808 married Penelope Russell, daughter of Dr. Charles Russell, a Loyalist, who went in exile in Guatemala as the Revolutionary War started and loss all his properties in the United States by war's end.