Alexander Spotswood was born in the Colony of Tangier, Morocco, Africa, about 1676 to Catharine (née Maxwell, c. 1638 - December 1709) and her second husband, Dr Robert Spottiswoode (September 17, 1637 - 1680), the Chirurgeon (surgeon) to the Tangier Garrison.
Through his father, Alexander is a grandson of Judge Robert Spottiswoode (1596–1646), a great-grandson of Archbishop John Spottiswoode (1565–1639), and a descendant of King Robert II of Scotland through the 2nd Earls of Crawford.
Alexander's older half-brother (by his mother's first marriage to George Elliott) was Roger Elliott (circa 1655 - May 15, 1714), who had become one of the first Governors of Gibraltar.
Following the death of Robert Spotswood, his mother had married thirdly, Reverend Dr. George Mercer, the Garrison's Schoolmaster.
Alexander had on May 20, 1693, become an Ensign in the Earl of Bath's Regiment of Foot.
Commissioned in 1698, and promoted to Lieutenant-Colonel in 1703, he had been appointed Quartermaster-General of the Duke of Marlborough's army the same year, and was wounded at the Battle of Blenheim the following year.
Spotswood had been appointed Lieutenant Governor of Virginia in 1710, under the nominal governorship of George Hamilton, 1st Earl of Orkney.
He is the first to occupy the new Governors Mansion, which many citizens think overly extravagant (its twentieth-century reconstruction is now one of the principal landmarks in Colonial Williamsburg).
He had intervened in 1711 in Cary's Rebellion in North Carolina, sending a contingent of Royal Marines from the Chesapeake to put down the rebellion.
A Tobacco Act requiring the inspection of all tobacco intended for export or for use as legal tender is passed in 1713.
The next year, he had founded the First Germanna Colony, and regulates trade with native Americans at another of his pet projects, Fort Christanna.
He buys three thousand two hundred and twenty-nine acres (thirteen square kilometers) at Germanna in 1715.
He leads the Knights of the Golden Horseshoe Expedition in 1716 up the Rappahannock River valley and across the Blue Ridge Mountains at Swift Run Gap into the Shenandoah Valley to expedite settlement.
The following year sees the foundation of the Second Germanna Colony and the repeal of regulation of trade with native Americans.
A Third Germanna Colony follows in 1719, and the following year Germanna will be made the seat of Spotsylvania County.