He was brought into Maryland during the English Civil War by Captain Giles Brent. William resided with the Jesuit priests at Port Tobacco where he received a catholic education. During the 1645 Revolution he was among those captured by adherent of Richard Ingle and taken prisoner to St. Mary's City. By 1651 he was employed by Giles Brent on Kent Island.
Williams home plantation in St. Mary's County was known as Kitt Martins Point and was sold in 1663 to James Jolly (an inn keeper) for 15,000 pounds of tobacco.
During his lifetime, he was a mariner, a captain and a major of the militia, planter, land speculator, Indian trader and interpreter, sheriff, gentleman justice, and delegate to the General Assembly.
Major William Boarman was one of the Gentleman Justices of St. Mary's County, Maryland; in 1678, he was presiding justice; from 1671-1675, he was a delegate to the general assembly; from 1678-1681, he was High Sheriff of Charles County, Maryland.
He participated with the Proprietary Forces in the Battle of Severn; participated in the Nanticocke Indian War of 1678. He defended the colonies against Indians. It is also noted that his home was the only one designated for trade with the Indians in St, Mary's County by those who were not designated to trade with the Indians."