In his father's seventy-fifth year Benedict Leonard appears deliberately to have courted royal favor in order to secure the restoration of the proprietorship after the third Lord's death, for in 1713 he publicly renounced the faith of the Calverts and united with the Church of England. Shortly thereafter he was elected to Parliament for Harwich in Essex. Angered by his son's desertion of the Catholic Church, Lord Baltimore cut off his allowance and the breach is said never to have been healed. However, Benedict Leonard secured an annuity from the Crown as well as a liberal income from the revenues of the Province through cooperation of the new governor, John Hart, in whose appointment he had a hand.

Upon the death of Charles, Third Lord Baltimore, in February, 1715, Benedict Leonard succeeded to the title and inheritance of his forefathers. He immediately petitioned the king for restitution of political control of Maryland, but before his plea could be acted upon, he died, scarcely two months after his father's death. Within the year King George I returned to Calvert's young son, Charles, the full proprietary powers. With this act the government of Maryland came again under the control of the Lords Baltimore.

Through marriage to lady Charlotte Lee, daughter of Earl of Litchfield and granddaughter of King Charles II and the Duchess of Cleveland, Benedict Leonard brought a strain of royal blood to the Calvert line and gained access to the court. However, contemporaries have disparaged his character and blamed him for the estrangement and separation from the lady Charlotte.

The portrait shows him garbed in the robes of a peer, his plumed hat resting upon a table. He presents a youthful appearance for a man of thirty-six, the age at which be became entitled to wear the trappings of rank. The painting includes a fine representation of the arms of the Maryland Palatinate.

The artist and date of the painting have not been established.