At the inauguration of Harvard President John Thornton Kirkland on November 14, 1810, Thacher was appointed to deliver the Latin congratulatory address,[4] a performance for which he received high praise.

[2] Not long after this event, Thacher was called to fill the pulpit of the New South Church in Boston, left vacant by Kirkland.

He began his pastorate with enthusiasm and success, but before many years his health failed, and the remainder of his life was a brave but unavailing struggle against consumption.

His sermon on the Unity of God, in which he gives a clear exposition of the Unitarian doctrine, was printed in Liverpool in 1816 without his knowledge, and reprinted in Boston and also in Worcester the next year.

This article incorporates text from this source, which is in the public domain: Potter, Alfred Claghorn; Bolton, Charles Knowles (1897).