[1][2] His father Peter Hairston, who was Presbyterian and probably Scots-Irish, had immigrated with his family from northern Ireland (or possibly Scotland) to Pennsylvania about 1728, probably escaping a drought.
[17] A local Justice of the Peace, Harrison took the oath of allegiance to the revolution in 1776, and previously had received his commission from Thomas Nelson, Jr. appointing him the "High sheriff" of Henry County.
[19][20] Hairston served in the House of Delegates of the Virginia General Assembly in the May 5, to June 28, 1777, and October 20 to January 24, 1778, Sessions with the other Henry county representative, Abram Penn.
He was one of the richest men in Franklin County, and after all his bequests were distributed, his estate was worth £499.1.6 (499 pounds, one shilling, sixpence).
"Hairston endowed each of his daughters- as did most fathers who were able to do so- with her own estate to control independently of her present or future husband.