In 1624, Jermyn was elected
Member of Parliament for
Bere Alston under the patronage of
Lord Mountjoy. In 1625 he was elected MP for
Leicester. He was subsequently elected MP for
Lancaster in 1626 and for
Clitheroe in 1628, sitting until 1629 when King Charles I decided to dissolve parliament. In 1626, Jermyn had been appointed as an
equerry to the king, and that year he publicly opposed attempts by the Commons to impeach the king's favourite, the
Duke of Buckingham. This included accidentally revealing the confidential views of the king’s immediate circle while criticising
Dudley Digges, who was leading the attempts to impeach Buckingham. Jermyn attended the royalist
Oxford Parliament in 1644. In the following year he succeeded to his father's estate, which was ostensibly worth £1,980 a year. However, all of his lands were mortgaged, and he went into exile after the eventual royalist defeat in the war. In January 1651, he returned to Suffolk where he lived quietly under
The Protectorate until his death in November 1659. ==Marriage and children==