He completed preparatory studies, and graduated from Yale College in 1810. He studied law at Tapping Reeve"s Litchfield Law School in Litchfield, was afterwards admitted to the bar in 1811.
Noah Webster named Ellsworth as one of the executors of his will of 1843. Ellsworth was appointed professor of law at Trinity College in 1827, which position he held until his death. (Judge Williams was married to Ellsworth"s sister) Aged 26, Ellsworth took up the reins of Congressman Williams" law practice, the largest in the state.
As an Anti-Jacksonian Ellsworth was elected to the Twenty-first, Twenty-second, and Twenty-third United States Congresses and served from March 4, 1829, to July 8, 1834 when he resigned.
Ellsworth was elected Governor of Connecticut 1838-1842. During his tenure, a progressive method for voter registration was constituted and a school commission was founded.
In 1847, Elsworth became judge of the Connecticut Supreme Court and served from 1847 to 1861, when, by the constitutional provision relative to age, he retired. He twice declined to accept the nomination to the United States Senate, and retired from public life.
Ellsworth died in Hartford on January 15, 1868.
The former Congressman and Governor is interred at the Old North Cemetery in Hartford. The lawyer and orator Rufus Choate said of Ellsworth before the Massachusetts General Assembly: "If the land of Shermans, Griswolds, Daggets and Williams, rich as she is in learning and virtue, has a sounder lawyer, a more upright magistrate, or an honester man in her public service, I know not his name.".