St. George Stock was the son of St George Henry Stock senior of Castle Connell, County Sligo and Frances Wilhelmina Atkinson of Rehins Parish, Ballynahaghish, County Mayo, who were married at St Peter’s Church, Dublin on 17 December 1844. He was the fourth of six children.
In 1868 St George junior went up to the University of Oxford from Victoria College, Jersey, and was matriculated from Pembroke College on 26 October 1868.
His granddaughter Heather Grace Angel was a Hollywood actress.