George was the son of Captain Samuel Brigham of Marlborough, Middlesex County, Massachusetts and Abigail Moore (Moor) Brigham of Sudbury, Middlesex County, Massachusetts. Abigail and Samuel were married on 23 August 1716 in Marlborough, Middlesex County, Massachusetts. Abigail and Samuel had eight children. They were: Samuel Brigham was born on 13 June 1717; Sybil (Sybella) Brigham was born on 15 October 1718; Mary Brigham was born on 13 April 1720; Abigail Brigham was born on 10 December 1721; Samuel Brigham was born on 03 March 1723; Phinehas Brigham was born on 18 December 1725; Uriah Brigham was born on 10 September 1727; and George Brigham was born on 17 March 1730. All the children were born in Marlborough, Middlesex County, Massachusetts.

George married Mary Bragg on 11 April 1754 in Shrewsbury, Worcester County, Massachusetts. Mary and George had seventeen children. They were: Phineas Brigham was born on 25 May 1755. He died on 03 July 1755; George Brigham was born on 22 July 1756; Phineas Brigham was born on 07 October 1757; Timothy Brigham was born on 11 February 1759; Louisa Brigham was born on 27 September 1760; Ashbel Brigham was born on 03 March 1762. He died on 27 September 1771; Mary Brigham was born on 18 December 1763; Thankful Brigham was born on 07 May 1765; Zerviah Brigham was born on 06 April 1767; Samuel Brigham was born on 26 January 1769. He died on 01 September 1771; Stephen Brigham was born on 07 January 1771. he died 03 March 1771; Ashbal Samuel Brigham was born on 02 March 1772; Mary Louisa Brigham was born on 06 May 1773. She died on 02 September 1775; Stephen Brigham was born on 08 August 1774; Francis Brigham was born on 24 December 1776; William Brigham was born on 02 April 1779; and Infant Brigham was born about 1781. All the children were born in Marlboro, Middlesex County, Massachusetts.