Leonard Bacon prepared for college at grammar school in Hartford, Connecticut; he graduated from Yale College in 1820 and from the Andover Theological Seminary in 1823. From 1825 until his death he was pastor of the First Church (Congregational) in New Haven, Connecticut, occupying a pulpit which was one of the most conspicuous in New England, and which had been rendered famous by his predecessors, Moses Stuart and Nathaniel W. Taylor. In 1866, however, though never dismissed by a council from his connection with that church, he gave up the active pastorate; still, in 1868 he was president of the American Congregational Union.