American military chaplain.

Chaplain at Castle William in Boston harbor (1780-81). Traveled to France, with an introduction to Franklin from Jane Collas and Jane Mecom (1781). Subsequently converted to Catholicism, was ordained by the archbishop of Paris (1787), and returned to Boston as a Catholic missionary.

Son of Cornelius and Sarah (Plaisted) Thayer of Boston. Received an honorary A.B. from Yale (1779).