Leach was born on his family's homestead, “Lansdowne”, in Randolph County, North Carolina, January 17, 1815. He attended the common schools and Caldwell Institute in Greensboro, North Carolina. He graduated from the United States Military Academy in 1838, studied law, and was admitted to the bar in 1842. Leach began his law practice in Lexington, North Carolina, and served in the State house of commons from 1848 to 1858. Leach died in Lexington, North Carolina on June 1, 1891, and is interred in Hopewell Cemetery, near Trinity, North Carolina.