He was appointed the same year lord-lieutenant of the West Riding of Yorkshire, and in 1677 received the Garter.
On the 10th of April 1689 he was created marquess of Carmarthen and was made lord-lieutenant of the three ridings of Yorkshire.
Deputy in 1865, he was from 1868 to 1880 Obergespan (lord-lieutenant), in which capacity he gained the reputation of an excellent administrator.
In 1755 he went to Ireland as secretary to the lord-lieutenant, a position which he held for one year only; and on his return to England he received a court appointment, having already been promoted major-general.
The lord lieutenant had a strong personal liking for Swift, who was also a friend of Lady Carteret's family.