Andrew was the son of a John Miller and Elizabeth (Eckhart) Miller, sister of Barbara (Eckhart) Everhart and sister of Christina (Eckhart) Leavengood. A letter from 1895 states that Andrew was a son of a brother of his mother-in-law, and confirms the relationships.
Andrew was a cabinet maker in Annapolis, Ohio. He married Margaret Everhart, the second child of Philip Everhart and Barbara Eckhart on February 22, 1818. They had 13 children, nearly all dying in infancy. Of their 13 children, Matilda Miller (?-1850) married James Reed, Milton Miller (?-1852), and Mary Miller was poisoned at school, John K. Miller (1830-?) was a railroad contractor and married twice; a younger child married a Keller G.W. Maxahaller in Perry County, Ohio.