Mansel won the Welsh seat of
Cardiff as a
Tory MP in the
1689 Parliamentary election. Although he held the seat until 1698, it wasn't until he won the seat of
Glamorgan in 1699 that he began to gain higher political offices. In 1701 he held the office of
High Sheriff of Glamorgan. In 1714 he was appointed
Comptroller of the Household to
Queen Anne, a position he held until 1708. Whilst Comptroller of the Household, Mansel was invested as a
Privy Council. From 1712 to 1714, he was
Teller of the Exchequer and from 1714 to 1715 he was
Vice-Admiral of South Wales and Governor of
Milford Haven. He also held the office of Chamberlain of South Wales from circa 1714. Mansel reduced his participation in politics in 1715, with a proxy attending Parliament in his stead. ==Death and legacy==