Formey was born in Berlin, Brandenburg, as the son of immigrant Huguenots. His mother died when he was three years old, and Samuel was brought up by two of his aunts. He was educated for the ministry, and at the age of twenty became pastor of the French Protestant church at Brandenburg. Having in 1736 accepted the invitation of a congregation in Berlin, he was in the following year chosen professor of rhetoric in the Collège Français there, and in 1739 professor of philosophy. His pupils included Louis de Beausobre, who was to become a philosopher and political economist of some standing in his own right.