Hosea's great-great-grandfather was a coproprietor with Roger Williams in Rhode Island in 1646. His mother died when he was twenty months old. His father was a frontier farmer who ministered without pay. There was no school in Richmond, New Hampshire, but Hosea educated himself. When he asked his Baptist father if an inanimate substance were made animate would it suffer everlasting misery, his father told Hosea that he would have to answer his own question.

The family migrated to Massachusetts, and Hosea studied the Bible and chose to become a minister preaching the gospel of universal salvation for all as a circuit rider. He became the pastor of the Second Universalist church in Boston from 1817 until his death in 1852, as well as founder and editor of The Universalist Magazine. His primary book, A Treatise on the Atonement (1805), proclaimed that a God of love would not condemn us to eternal punishment.