He matriculated at Trinity College, Cambridge at Easter 1615 and was admitted at Gray's Inn on 6 November 1616.
[1] Pelham was elected Member of Parliament for Grimsby in 1621 and was re-elected in 1625, 1626 and 1628.
He sat until 1629, when King Charles decided to rule without parliament for eleven years.
[2] In April 1640, Pelham was elected MP for Grantham in the Short Parliament.
He held the post of Speaker for a short time in 1647, when William Lenthall temporarily fled from London.