George MacDonald, under whom Blackford had studied law, left his law practice in the east and moved to the Indiana in 1818. Blackford began courting his daughter Caroline, who was fourteen years younger than himself. They were married on December 23, 1819, in Vincennes by Reverend Samuel T. Scott. Their brief marriage was strained because of the age difference. Caroline wished to entertain and enjoyed the high society that Blackford's position brought, while Blackford preferred to live reclusively. They had one son, George, born on May 3, 1821. Caroline died in childbirth, a shock from which Blackford never fully recovered and leading him to become very protective and invested in his son. Blackford wrote to his mother of his unhappiness in marriage, and, after his wife's death, he vowed to never marry again.