The 3rd Earl of Carlisle first spoke to William Talman, a leading architect, but commissioned Vanbrugh, a fellow member of the Kit-Cat Club, to design the building. Castle Howard was that gentleman-dilettante's first foray into architecture, but he was assisted by Nicholas Hawksmoor.
Vanbrugh's design evolved into a Baroque structure with two symmetrical wings projecting to either side of a north-south axis. The crowning central dome was added to the design at a late stage, after building had begun. Construction began at the east end, with the East Wing constructed from 1701–03, the east end of the Garden Front from 1701–06, the Central Block (including dome) from 1703–06, and the west end of the Garden Front from 1707–09. All are exuberantly decorated in Baroque style, with coronets, cherubs, urns and cyphers, with Roman Doric pilasters on the north front and Corinthian on the South. Many interiors were decorated by Giovanni Antonio Pellegrini.