The earliest of the celebrated Montgomerys was Comte Roger de Montgomery (11th century), companion in arms to William the Conqueror. William granted him extensive lands in recognition of his having sustained the Norman holdings in France during the first phase of the Conquest. From England and Wales, the Montgomerys established themselves in Scotland, and at the time of the Plantation of Ulster (early 17th century), many settled in County Antrim and County Down. This was true of the branch of the family of which Sir Bernard Montgomery of Alamein was the most famous 20th century representative. It was also true of John Warwick Montgomery's family. From the little townland of Ballywoodock near Ballymena, County Antrim, John Warwick Montgomery's great-grandfather, for whom he was named, emigrated to America during one of the dreadful Irish potato famines of the 1840's. He settled in Warsaw, near Rochester, New York, and practiced the trade of selling and repairing shoes. His son Frank established a lumber, coal and animal feed business in Warsaw, and John Warwick Montgomery's father (Maurice Warwick Montgomery) and uncle (James Montgomery) later divided and ran those businesses. In 1991, John Warwick Montgomery returned to his roots in the United Kingdom.
In recognition of the Northern Irish connections of the family, John Warwick Montgomery was granted arms by the Queen through the office of the Norroy and Ulster King of Arms of the Royal College of Arms. He also holds the feudal lordship of Morris, once possessed by the father of Lord Chancellor and scientific philosopher Francis Bacon; the barony of Kiltartan in Ireland (made famous by poet Lady Gregory); and is Comte de Saint-Germain de Montgommery, on the basis of land holdings in the Norman French territory from which Comte Roger Montgomery came to England at the time of the Conquest.