At the 1690 English general election, Seymour was returned as Member of Parliament for West Looe.
[2] Seymour succeeded his father on 17 February 1708 to the baronetcy and the huge original Bradley House in Wiltshire.
At the 1710 British general election, he was returned as MP for Great Bedwyn with Lord Bruce.
[2] Seymour completed Bradley House in 1710, which enabled the family to leave their crumbling seat at Berry Pomeroy Castle in Devon.
By his wife he had twelve children:[4] His estate passed to his eldest son, Edward, who reunited the two branches of the Seymour family when he inherited the dukedom of Somerset in 1750.