Fenner was born in Providence in the Colony of Rhode Island and Providence Plantations. He graduated from Brown University in 1789, and was married to Sarah Whipple Jenckes (his first cousin, once removed) on November 17, 1792. He served as United States senator from 1805 to 1807, then gave up his senatorship to become Governor of Rhode Island, two years after his father died in office.
Fenner was born in Providence, Rhode Island, and graduated from Brown University in 1789. He married Sarah Whipple Jenckes (his first cousin, once removed) on November 17, 1792. He served as a U.S. Senator from 1805 to 1807 before becoming the Governor of Rhode Island after his father's death in office.