Born at Berry Pomeroy Castle of a family greatly influential in the Western counties, he was a descendant of Edward Seymour, 1st Duke of Somerset, in the senior line. (Because of the adultery of the Duke's first wife, the Dukedom had been entailed with preference to his sons by his second marriage.) A skilled debater and politician, he was twice Speaker of the House during the Cavalier Parliament, the first non-lawyer to be chosen for that position for a considerable time.
Though able, Seymour's character was marred by his haughty pride in his ancestry (much like his cousin, the 6th Duke of Somerset) and by venality. However, his influence was much courted, and he led a powerful faction of Western members in Parliament. An opponent of the Exclusion Bill and a quintessential country gentleman, his Tory credentials were impeccable.
From the security of this position, Seymour moved that the Loyal Parliament investigate the irregularities surrounding the election of its members before it granted any revenues to James II, but as no other member dared to second it, it brought about no immediate consequence. He continued to oppose the arbitrary measures of James throughout his reign.
During the Glorious Revolution, he was one of the first Tories to declare for the Prince of Orange. The remarks that supposedly passed between the two on the first meeting are indicative of his pride of birth: "I think, Sir Edward," said the Prince, "that you are of the family of the Duke of Somerset." "Pardon me, your highness," replied Seymour, "the Duke of Somerset is of my family." However, he adhered to the Tory party, acting as a sort of whip or manager, and remained a vigorous rhetorical opponent of the Whig. He particularly attacked Lord Somers, the Chancellor, and managed the several attempts made to remove him from office. In 1699, the death of his third son, Popham Seymour-Conway, from the effects of a wound incurred in a duel with Captain George Kirk, prompted him to make an attack upon the standing army.
He seems to have suffered from diabetes in later life, an exchange of wit between Seymour and his physician, Dr. Ratcliffe, being recorded in Joe Miller's Jests. He died at Bradley House, Maiden Bradley.
Family
In September 1661, he married Margaret Wale (d. bef. 1674), by whom he had two children:
