He is said to have been Charles's closest and most trusted servant, largely as a result of his knowledge that the king did not like to be approached on matters of business.
Baptist was appointed Groom of the Bedchamber to the Duke of York (the future James II) in 1662 and Keeper of the Privy Purse to the King three years later, thanks to the influence of Charles's mistress, Barbara Palmer (née Villiers), Countess of Castlemaine.
For example, according to Clarendon's biography, after the Great Fire of London in 1666, he remarked that it was welcomed, to make the city more controllable.
The Whig faction in parliament, led by the Earl of Shaftesbury and the Duke of Buckingham, was pressing the king to divorce his barren queen, Catherine of Braganza, and remarry to produce a Protestant heir.
However, he remained Ranger of Windsor Great Park, and continued to live at what later became known as Cumberland Lodge, until his death.