Robert Carter I, known as King Carter, turned inherited property into a commercial and political enterprise in colonial Virginia. He served as a Lancaster County justice, militia commander, and customs official, and entered the House of Burgesses in 1691. Elected speaker in 1696, he presided during the 1696 and 1697 sessions. He became colonial treasurer in 1699 and took his seat on the governor's Council in 1700, remaining a councillor until his death.

Carter's wealth grew through plantation agriculture, commerce, and his agency for the Northern Neck Proprietary in 1702–1711 and 1722–1732. His position gave him access to surveyors and desirable tracts, which he patented for himself and his children. Enslaved workers supplied the labor on his tobacco plantations, supervised through an hierarchy of overseers. He also managed transport and trade and acted as an agent for slave traders. His correspondence records close attention to production, debts, shipping, and estate management.

In politics he defended the interests of Virginia's leading planters against governors Francis Nicholson and Alexander Spotswood. As the Council's senior member, he acted as governor after Hugh Drysdale's death, serving from August 1726 until William Gooch's arrival in September 1727. He also supported the College of William and Mary and financed a new Christ Church in Lancaster County. At his death in August 1732, his vast estates passed through a detailed will to his children and grandchildren.