When John Hart was born on 31 December 1814, in Bucks, Pennsylvania, United States, his father, John Hart, was 43 and his mother, Sarah Dugan, was 29. He married Mary Eliza Johnson on 28 December 1843, in Bucks, Pennsylvania, United States. They were the parents of at least 2 sons and 3 daughters. He died on 9 September 1894, in Petersburg, Virginia, United States, at the age of 79, and was buried in Blandford Cemetery, Petersburg, Virginia, United States.