Heiskell was from the Sparta, Tennessee, area. He served in the 28th General Assembly (1849–51) representing White, Fentress, Jackson, Overton, and Van Buren counties. Afterwards, he served as a judge. Following the state's ordinance of secession and the outbreak of the Civil War, he represented Tennessee in the First Confederate Congress from 1862 to 1864.
Following the end of the war, he returned to his legal practice. He was a member of the Tennessee House of Representatives during the 39th General Assembly, 1875-77.
- McBride & Robinson, p. 275.
- Robert M. McBride and Dan M. Robinson, eds., Biographical Directory of the Tennessee General Assembly, Volume I, 1796-1861. (Nashville: Tennessee State Library and Archives and Tennessee Historical Commission, 1975).