He was the 3rd son of Sir Edward Seymour, 4th Baronet (d1708) of Berry Pomeroy in Devon, by his second wife Laetitia Popham (of which marriage he was the eldest son), a daughter of Alexander Popham (1605 – 1669), Member of Parliament, of Littlecote in Wiltshire.
Considerable suspicion was aroused by this transaction, as it displaced Sir Arthur Rawdon, 2nd Baronet, Conway"s nephew, from the succession. lieutenant was suspected that his father Sir Edward Seymour, 4th Baronet, had taken advantage of the Earl"s senility to bring it about. On 4 June 1699, during a drunken duel with Captain George Kirk of the Royal Horse Guards, Seymour-Conway was wounded in the neck.
He succumbed to the effects of the wound two weeks later and on 18 June died in London.
In 1697 Seymour-Conway became Member of Parliament for Lisburn, site of his new estates, in the Irish Parliament.
