George Mercer was born on June 23, 1733, at Marlborough in Stafford County, Virginia. He was a son of John Mercer, one of the colony’s most accomplished lawyers and legal writers, and Catherine Mason Mercer. His elder brother James Mercer later became a judge and Revolutionary statesman. The family belonged to Virginia’s prosperous planter gentry and maintained extensive legal, commercial, and kinship connections. Their wealth, like that of comparable Chesapeake families, was rooted in land and enslaved labor. George grew up in an unusually intellectual household. His father assembled a substantial library and compiled an important digest of Virginia law. Although George did not ultimately make law his principal profession, exposure to books, land claims, court proceedings, and political discussion equipped him for later administrative work. He received the private education expected of a gentleman’s son, likely including classics, mathematics, writing, riding, and surveying-related skills. Precise details of his tutors and curriculum are not consistently preserved. The Mercers were deeply involved in western land speculation through the Ohio Company of Virginia. As a young man George learned to think of the colony not only as the settled Tidewater but as an expanding territory extending toward the Ohio Valley. That interest brought him into contact with other ambitious young Virginians, including George Washington. Military opportunity arrived during the French and Indian War. Mercer joined the Virginia Regiment and served as an officer, gaining experience in frontier campaigning, supply, recruitment, and relations among provincial and British forces. He was wounded during the fighting and developed a reputation for courage. His service also strengthened ties with Washington and other veterans who would later divide over imperial politics.