John Symes matriculated Feb. 23, 1588 at Exeter College, Oxford, received his B.A. in 1591, and was a student at Lincoln's Inn 1589.

He served as a justice of the peace in Somerset 1608-1645, sheriff of Somerset 1626-1627, member of the Court of Oyer and Terminer for the Western Circuit 1629-1643, Deputy Lieutenant of Somerset 1637-1642, commissioner of Assessment (1641-1642) and Array (1642), and several other public offices. His chief residence was Poundisford Lodge at Pitminster, Somerset, and he was also lord of the manors of Barwick and West Coker.

On a personal level, his opponents of more genteel background described his father, a successful merchant, as "a peddler, and a base fellow." Indeed it was John's marriage which was contracted on Dec. 29, 1595 that allied him with a lineage based family. Along with his brother-in-law, Sir John Horner, Symes oversaw part of the polls during elections in Somerset. In 1624 he was elected to Parliament and served on a few committees. Described as "a rich and decrepit man", he supported the King during the Civil War, but was charged by Sir Richard Grenville "with some inclination to the rebels" and fined £1000. He never paid the fine, but compounded with Parliament for his delinquency with a fine of £945, and then was charged with concealing mortgages to the value of £5000. He sought "a repose for his old age" in Gloucestershire where he died in his 89th year. He was the only member of his immediate family to sit in Parliament.