When Guy Mark Mankin was born on 11 September 1896, in Alexandria, Virginia, United States, his father, William Armour Mankin, was 28 and his mother, Elisabeth Guy Blake, was 22. He married Leona Gertrude Davis in 1918, in Philadelphia, Pennsylvania, United States. They were the parents of at least 1 son. He immigrated to New York City, New York, United States in 1929 and lived in District 722, Fulton, Georgia, United States in 1940 and Fulton, Kalamazoo, Michigan, United States in 1957. He died on 19 September 1957, in Fulton, Georgia, United States, at the age of 61, and was buried in Riverside Cemetery, Macon, Bibb, Georgia, United States.