Blackford studied at the Western Theological Seminary. He was ordained by the Presbyterian Church in the United States of America in April 20, 1859.
He and his wife Elizabeth Blackford arrived at Brazil in July 25, 1860, where they met Ashbel Green Simonton, Elizabeth's brother.
In Brazil Blackford planted and organized numerous local churches. He cooperated with his brother-in-law in many of the projects that marked the first years of Presbyterianism in Brazil.
Blackford was one of the leaders that emancipated the Presbyterian Church in Brazil from the mother churches in the United States, in 1888.
He died in Atlanta, while he was on vacation. Contemporary accounts say that shortly before he died, he was singing hymns in Portuguese.