His ancestors were among the first settlers of Sheffield, where he spent his early life, alternately working upon his father's farm and attending the village school.

The strict Calvinism that colored the religious life around him was greatly tempered by his intercourse with his cousin, Paul Dewey, who was an able mathematician and a skeptic with regard to the prevailing theology.

He soon became a Unitarian, and was appointed to be the assistant of Dr. William Ellery Channing, in Boston, with whom he formed a lasting friendship, and whose Church he supplied during its pastor's travels in Europe.

He was compelled to resign his charge in 1848, and retired to his farm in Sheffield, where he prepared a course of lectures for the Lowell Institute of Boston, on the "Problem of Human Life and Destiny", which course was repeated twice in New York, and delivered in many other cities.

His daughter, Mary Elizabeth Dewey, born in Sheffield, was an author and editor; she translated George Sand's novel The Miller of Angibault and edited Life and Letters of Catharine M. Sedgwick (New York, 1871).