Kemys was the eldest son of Edward Kemys of Pertholey and Maesgenwith and his wife Anne Bray, daughter of Reginald Bray of Barrington, Gloucestershire.
He was educated at Eton College from 1705 to 1711, succeeding his father in 1710.
[2] At the 1722 British general election, Kemys was returned unopposed as a Tory Member of Parliament for Monmouth Boroughs by the Duke of Beaufort.
He was returned again unopposed at the 1727 British general election.
This article about a Member of the Parliament of Great Britain (1707–1800) representing a Welsh constituency is a stub.