At the age of 24 Charles came as governor to Maryland to remain, except for one visit to his father, till after latter's death. Upon his accession to the barony he went again to England, but soon returned to the colony as first resident proprietor. After the grant of Pennsylvania in 1681, he was obliged to defend his rights along the northern boundary against the claims of William Penn. Thanks to the patronage of James II, Penn was able to get the better of Calvert, who vainly invoked the terms of the charter and the favorable precedents established under preceding regimes. At the height of the bitter controversy both proprietors returned to England, but before asettlement could be reached another revolution brought William and Mary to the throne and a new problem to Charles Calvert. Civil disorder broke out in Maryland, culminating in the Protestant Revolution, whereupon the Crown assumed political control. Though his property rights and revenues were undisturbed. Baltimore thus lost the power to govern. In 1692 the first royal governor, Lionel Copley, arrived in Maryland. From this date until his death Charles exerted all his efforts in an unsuccessful attempt to secure restoration of proprietary privileges. He died in England in 1715.

Firm in will and genuinely concerned for the welfare of his Maryland subjects, Charles lacked the prudence of his father and grandfather and relied too heavily on the outdated prerogatives of the feudal government contemplated by the charter. The new spirit of representative government that had possessed Englishmen on both sides of the Atlantic steadily diminished his power, and loss of the royal support that had shielded the rights of his predecessors reduced the proprietary position during the later years to one of mere ownership of Maryland soil.

The portrait is signed by Sir Godfrey Kneller, court painter to five English soveregins.