Mark Jefferson Hargin was born around 1818 in New York. He got married by the early 1840s, and his son Charles was born around 1842. His wife probably died sometime before 1850. By 1850, he was living in Lansing, New York, and working as a farm laborer. He married Joanna Ryan on November 5, 1850, and they had three children: Lettie, born on September 3, 1851; Ellen, born on August 10, 1853; and Edward, born on October 21, 1855. Hargin enlisted in the Union army on August 6, 1862, and mustered in as a wagoner in Company D of the 143rd New York Infantry on October 8, 1862. He died of disease at Fort Monroe, Virginia, on July 27, 1863.