He was the Member of Parliament for Bury St Edmunds before being removed during Pride's Purge in 1648, but was returned to the House of Commons as the MP for Suffolk shortly before his death in 1654.

[3] In October 1640 Spring stood for election in Bury St Edmunds, but was defeated in the face of the superior influence of his relations, the Jermyns.

Towards the end of his year in office, the king also granted Spring a hereditary title, creating him a baronet, of Pakenham in the Baronetage of England, on 11 August 1641.

Spring travelled the eastern counties of England, helping to recruit soldiers to the Parliamentarian army and maintain Parliament's control of East Anglia.

[1] In November 1644 he wrote to the Committee of Both Kingdoms to express his concern at what he perceived to be the growing number of radical antinomians and anabaptists in East Anglia.

He was a staunch friend of Sir Nathaniel Barnardiston of Kedington, a notable advocate of the Puritan cause, upon whose death he wrote an acrostic elegy.

His voting record in the Commons was strongly influenced by his Presbyterian beliefs and in November 1646 he was appointed to a committee to oversee the selling of the estates of bishops.

On 5 September 1646 Spring was among the delegation sent by parliament to the City of London to raise £200,000 needed to pay off the Scots Army in England.

The First Protectorate Parliament assembled in September 1654 but Spring is not recorded as having played any part in its proceedings, likely as a result of his declining health.